Kinematic Graphs Slope Velocity is the slope of Displacement Instantane

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Kinematic Graphs Slope Velocity is the slope of Displacement Instantaneous Velocity Instantaneous Acceleration Average vs. Instantaneous Derivative Infinitely small time period (dt) Velocity from Displacement Graph Sketching Differentiation Graph Sketching Differentiation Going the other way area under the curve Displacement is the Area Under the Velocity Curve What if velocity isn?t a straight line? Integration Infinitely small time periods Graph Sketching Integration Graph Sketching Integration

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* Dr. Sasho MacKenzie – HK 376 * Kinematic Graphs Graphically exploring derivatives in addition to integrals * Dr. Sasho MacKenzie – HK 376 * Slope X Y (0,0) (4,8) 8 4 Slope = rise = DY = Y2 ? Y1 = 8 ? 0 = 8 = 2 run DX X2 ? X1 4 ? 0 4 * Dr. Sasho MacKenzie – HK 376 * Velocity is the slope of Displacement X Y (0,0) (4,8) 8 4 Average Velocity = rise = DD = D2 ? D1 = 8 ? 0 = 8 m = 2 m/s run Dt t2 ? t1 4 ? 0 4 s Displacement (m) Time (s) * Dr. Sasho MacKenzie – HK 376 * The displacement graph on the previous slide was a straight line, therefore the slope was 2 at every instant. Which means the velocity at any instant is equal so that the average velocity. However if the graph was not straight the instantaneous velocity could not be determined from the average velocity * Dr. Sasho MacKenzie – HK 376 * Instantaneous Velocity The average velocity over an infinitely small time period. Determined using Calculus The derivative of displacement The slope of the displacement curve * Dr. Sasho MacKenzie – HK 376 * Instantaneous Acceleration The average acceleration over an infinitely small time period. Determined using Calculus The derivative of velocity The slope of the velocity curve * Dr. Sasho MacKenzie – HK 376 * Average vs. Instantaneous Average Velocity = rise = DD = D2 ? D1 = 8 ? 0 = 8 m = 2 m/s run Dt t2 ? t1 4 ? 0 4 s * Dr. Sasho MacKenzie – HK 376 * Derivative The slope of the graph at a single point. Slope of the line tangent so that the curve. The limiting value of DD/ Dt as Dt approaches zero. * Dr. Sasho MacKenzie – HK 376 * Infinitely small time period (dt) Tangent line Instantaneous Velocity Displacement Time * Dr. Sasho MacKenzie – HK 376 * Velocity from Displacement The graph below shows the vertical displacement of a golf ball starting immediately after it bounces off the floor in addition to ending when it lands again. * Dr. Sasho MacKenzie – HK 376 * Graph Sketching Differentiation 0 + 0 Slope * Dr. Sasho MacKenzie – HK 376 * Graph Sketching Differentiation * Dr. Sasho MacKenzie – HK 376 * Going the other way: area under the curve Area under curve = Height x Base = DY x DX = 4 x 2 = 8 * Dr. Sasho MacKenzie – HK 376 * Displacement is the Area Under the Velocity Curve Displacement = V x Dt = 4 x 2 = 8 m * Dr. Sasho MacKenzie – HK 376 * What if velocity isn?t a straight line? * Dr. Sasho MacKenzie – HK 376 * Integration Finding the area under a curve. Uses infinitely small time periods. All the areas under the infinitely small time periods are then summed together. D = •Vdt = †VDt * Dr. Sasho MacKenzie – HK 376 * Infinitely small time periods D = •Vdt = V1Dt1 + V2Dt2 + V3Dt3 + * Dr. Sasho MacKenzie – HK 376 * Graph Sketching Integration * Dr. Sasho MacKenzie – HK 376 * Graph Sketching Integration * Dr. Sasho MacKenzie – HK 376 * Indicate on the acceleration graph below the location of the following point(s). Place the letter on the graph. A. Zero velocity B. Zero acceleration C. Max velocity D. Min velocity E. Max acceleration F. Min acceleration 0 1 s 2 s 3 s -1 2 * Dr. Sasho MacKenzie – HK 376 * Indicate on the velocity graph below the location of the following point(s). Place the letter on the graph. A. Zero velocity B. Zero acceleration C. Max velocity D. Min velocity E. Max acceleration F. Min acceleration G. Max displacement H. Min displacement 0

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CritŠres bact‚riologiques daction des antibiotiques les concentrations

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CritŠres bact‚riologiques d?action des antibiotiques les concentrations critiques Pharmacodynamie des antibiotiques La CMI D‚termination de la CMI D‚termination de la CMI par une m‚thode de dilution en milieu liquide D‚termination de la CMI D‚termination de la CMI E test E test principe E test lecture E test Difficult‚s dans la d‚termination de la CMI Difficult‚ dans l?‚valuation d?une CMI li‚e … l?h‚t‚rog‚n‚it‚ du pr‚lŠvement qui peut ˆtre constitu‚ d?un m‚lange de germes ayant des CMI diff‚rentes Difficult‚s dans l?‚valuation d?une CMI li‚es aux aspects techniques de la mesure de la CMI Le pas de dilution ( , 2, 4, 8.) donne une progression g‚om‚trique Limite de la CMI sa valeur d‚pend de la taille de l?inoculum MIC serum vs. lait CMI Action des antibiotique in vivo vs in vitro Action des antibiotiques in vivo vs in vitro (ex un abcŠs) Utilit‚ et usage des CMI Th‚rapeutiques Utilisation des CMI … des fins ‚pid‚miologiques Distribution des CMI de la gentamicine pour E Coli (population sauvage) La CMB Rapport CMB / CMI 3 La CPM Concentration pr‚ventive de mutants (CPM) & notion de fenˆtre de s‚lection la concentration … prendre en compte pour pr‚venir l?‚mergence de r‚sistance (surtout pour des quinolones) CMP le problŠme CPM (Concentration Pr‚ventive de Mutants) Notion de fenˆtre de s‚lection La fenˆtre de s‚lection Notion de fenˆtre de s‚lection La fenˆtre de s‚lection Les mutants ne sont pas s‚lectionn‚s en dessous de la CMI et au dessus de la CPM Strat‚gies pour limiter le d‚veloppement de r‚sistance AUC/MIC > 25 h Emergence vs. s‚lection de mutants r‚sistants par les quinlones Antibiotiques pour lesquels le concept de fenˆtre de s‚lection s?applique

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* CritŠres bact‚riologiques d?action des antibiotiques : les concentrations critiques P.L. TOUTAIN ECOLE NATIONALE VETERINAIRE T O U L O U S E Update mars 2012 Pour aller sur notre site si vous avez r‚cup‚r‚ nos dia ailleurs * Pharmacodynamie des antibiotiques ParamŠtres in vitro d?efficacit‚ ParamŠtres in vivo d?efficacit‚ * Indicateurs d?action & d?effet des antibiotiques In vitro: critŠres bact‚riologiques Statiques CMI, CPM, . Prise en compte du temps EPA Dynamiques vitesse bact‚ricide in vitro & in vivo : indices mixtes PK/PD AUC/MIC, Cmax/MIC, Temps au dessus de la CMI In vivo bact‚ri‚mie, hyperthermie, leucocytose, GMQ, survivants/d‚cŠs, ‚volution des flores * PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * CritŠres bact‚riologiques 1-In vitro & statique Buts tablir le niveau de sensibilit‚ des pathogŠnes … l?antibiotique (mesure de puissance de l?antibiotique) Concentration minimale antibact‚rienne (CMA) Concentration minimale inhibitrice (CMI) Concentration minimale bact‚ricide (MBC) Pr‚venir le d‚veloppement d?une population de mutants r‚sistants Concentration pr‚ventive de mutants (CPM) * CMA : Concentration Minimale Antibact‚rienne ? Concentration inf‚rieure … la CMI entraŒnant les premiŠres modifications morphologiques ou physiologiques de la bact‚rie ex. : production d’enzymes autolytiques / attachement in vivo/ acc‚l‚ration de la phagocytose PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * 1-La CMI CMI ( Concentration Minimale Inhibitrice): d‚finition Plus petite concentration (mg/L) capable, in vitro , d’interdire une croissance bact‚rienne pendant 24h mesure effectu‚e avec un inoculum de d‚part de 105 / ml Concentration bact‚riostatique Evalu‚ indirectement en utilisant les antibiogrammes * * D‚termination de la CMI M‚thode de dilution en milieu liquide (macrom‚thode avec des tubes ou microm‚thode avec des cupules) M‚thode de dilution en milieu solide E-test (diffusion sur disque) D‚termination avec des automates * D‚termination de la CMI par une m‚thode de dilution en milieu liquide pr‚paration d?une s‚rie de tubes … h‚molyse avec le milieu de culture liquide (2 mL) pour constituer une gamme de concentrations de l’antibiotique … tester (ex: 0.5 1, 2, 4, 8, 16 æg/mL c.a.d selon une progression g‚om‚trique de base 2. Un tube (contr“le) servira de t‚moin de croissance de la souche … tester. On ajoute la mˆme quantit‚ de germes dans chacun tube (inoculum: 5 x 106 / ml). La galerie pr‚par‚e sera incub‚e … 37øC pendant 18 heures. lecture … l’oeil nu * 0 0.25 0.5 1 2 4 8 16 32 CMI : Concentration dans le premier tube pour lequel il n’y a pas de croissance visible aprŠs 24h … 37øC CMI D‚termination de la CMI * D‚termination de la CMI Broth dilution * E-test * E-test : principe Un gradient de concentrations d’antibiotique est obtenu sur une bandelette plastifi‚e. La bandelette (une bandelette par antibiotique) est d‚pos‚e … la surface d’une boite de P‚tri ensemenc‚e avec la suspension de la bact‚rie … tester * E-test :lecture AprŠs un nuit d’incubation … 37øC dans une ‚tuve, on peut lire directement la valeur de la CMI au niveau de la zone … lire. PL Toutain Ecole V‚t‚rinaire Toulouse E-test Avantages mesure plus pr‚cise de la CMI qu’avec un disque Utilis‚ en MH pour des infections s‚vŠres ou pour certains germes En MV, devrait permettre de s?affranchir de la principale limite de l?antibiogramme qui est la valeur des breakpoints retenus qui sont ceux de la MH Limites Cher et long … r‚aliser et non valid‚ en MV par les organismes normatifs * Difficult‚s dans la d‚termination de la CMI P.Lees * Difficult‚ dans l?‚valuation d?une CMI li‚e … l?h‚t‚rog‚n‚it‚ du pr‚lŠvement qui peut ˆtre constitu‚ d?un m‚lange de germes ayant des CMI diff‚rentes * Sensibilit‚ in vitro … l?amoxicilline et la gentamicine de 20 isolats diff‚rents de E Coli provenant du mˆme pr‚lŠvement On notera l?h‚t‚rog‚n‚it‚ des r‚sultats sugg‚rant que la population responsable de l?infection n?est pas homogŠne mais se pr‚sente plut“t comme un ®ÿessaimÿ¯ avec des germes ayant des CMI individuelles allant de 1 … 10 * Difficult‚s dans l?‚valuation d?une CMI li‚es aux aspects techniques de la mesure de la CMI * Le pas de dilution (1, 2, 4, 8) donne une progression g‚om‚trique La vraie CMI est inf‚rieure … celle qui est annonc‚e; elle est situ‚e entre le premier tube ayant une absence totale de croissance et le pr‚c‚dent Biais potentiel de 100% * Effet inoculum (faible) pH CO2, O2 Amino-acides N‚cessit‚ d’une standardisation des essais pour garantir leur reproductibilit‚ (CLSI) Influence des conditions in vitro d’‚valuation sur les r‚sultats * Lorian, p35 influence du pH sur l?action des antibiotiques PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * Limite de la CMI : sa valeur d‚pend de la taille de l?inoculum * – Certains AB (Bˆtalactamines, Quinolones ) ont leur activit‚ r‚duite en pr‚sence d’une population bact‚rienne importante (ce qui est le cas lors d?infection) – in vivo , on peut atteindre des densit‚s de 1010 – 1011 UFC alors que les CMI sont mesur‚s … 105 UFC – Importance de commencer rapidement une antibioth‚rapie (m‚taphylaxie) L’effet inoculum sur la d‚termination de la CMI PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * Objectives: So that determine the relationship between the density of bacteria (St Aureus) in addition to the PD of 6 antibiotics (ciprofloxacin, gentamicin, vancomycin, linezolide). Methods: In vitro time?kill, MIC estimation & PK/PD simulations Results: Inoculum effects on ef?cacy in consideration of all 6 antibiotics (density-dependent declines in the rate in addition to extent of antibiotic-mediated killing in addition to increases in MIC). PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * MICs estimated alongside different inoculmum densities, relative so that that MIC at 2×105 PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * Conclusions: PK/PD indices would be more predictive of the efficacy of antibiotics if, instead of using conventional estimates of the MIC, density dependent functions of MICs were employed as the denominators of these * Effet matrice sur la d‚termination de la CMI s‚rum Lait Exsudat Urine Bile LCR * MIC: serum vs. lait Staphylococcus aureus N‚cessite 4 fois plus d?antibiotique pour ˆtre inhib‚ dans le lait que dans le plasma * CMI: Action des antibiotique in vivo vs in vitro PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * Diff‚rences entre les conditions in vitro et in vivo pour d‚terminer une CMI In vitro Concentrations statiques pH physiologique, conditions optimales pour la croissance Milieu sans prot‚ine, tout l?antibiotique ‚tant libre valuation arbitraire … 24 h Pas de systŠme immunitaire Inoculum de faible taille et constant In vivo Concentrations variables Conditions de croissance variables et limitation possible … la croissance Pr‚sence de prot‚ines r‚duisant la fraction libre valuation possible in vivo mais pas … un temps pr‚d‚termin‚ SystŠme immunitaire coop‚ratif Inoculum de taille variable * ? Acidit‚ de l’abcŠs ? Ana‚robie ? Conditions diff‚rentes de la p‚riph‚rie au centre ? Populations bact‚riennes variables en taille et en vitesse de croissance ? Peut contenir une population mixte ? Inactivation possible des aminoglycosides et des sulfamides Action des antibiotiques in vivo vs in vitro (ex : un abcŠs) * Utilit‚ et usage des CMI Th‚rapeutiques s‚lection rationnelle d’un antibiotique Epid‚miologiques surveillance des r‚sistances * La CMI est consid‚r‚e comme une bonne approximation de la concentration libre d?antibiotique qu?il est n‚cessaire d?obtenir au site d?infection pour ‚radiquer un pathogŠne C?est la raison pour laquelle les concentrations plasmatiques des antibiotiques sont ®ÿcompar‚es ÿ¯ aux CMI des pathogŠnes extracellulaires (pour les intracellulaires, cela est diff‚rent) * La CMI est le critŠre PD retenu dans la construction des indices PK/PD d?efficacit‚ T>MIC AUC/MIC Cmax/MIC * Utilisation des CMI … des fins ‚pid‚miologiques Pour avoir accŠs a la base europ‚enne des CMI des diff‚rents pathogŠnes et pour les diff‚rents antibiotiques ( y compris certains antibiotiques d?usage strictement v‚t‚rinaire), pour connaŒtre les valeurs critiques des antibiogrammes (S/I/R) , etc. aller sur le site Eucast2 * Distribution des CMI de la gentamicine pour E Coli (population sauvage) * La CMB * CMB : Concentration minimale bact‚ricide Plus petite concentration (mg/L) capable, in vitro , d’entraŒner une inhibition irr‚versible de la croissance bact‚rienne (mort bact‚rienne) En pratique, ‚radication de 99.9% (3 log) d’un inoculum bact‚rien (106) en 18 – 24h * 4 8 16 32 64 CMB : Concentration dans le premier tube repiqu‚ avec la culture du tube de la CMI pour lequel il n’y a pas de recroissance visible (correspond au premier tube st‚rilis‚) CMB D‚termination de la CMB CMI Tous les tubes sont ensemenc‚s avec la culture du tube ayant donn‚ la CMI (tube non st‚rile) Recroissance Pas de recroissance * La bact‚ricidie s’effectue selon des dynamiques temporelles variables et pertinentes … connaŒtre On pr‚fŠre ‚valuer la vitesse de bact‚ricidie … la CMB CMB : Concentration minimale bact‚ricide * Rapport CMB / CMI ? Ph‚nomŠne de tol‚rance : si R > 32 ? Antibiotiques bact‚riostatiques vs bact‚ricidies (bact‚ricides si CMB = CMI) PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * 3-La CPM PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * Concentration pr‚ventive de mutants (CPM) & notion de fenˆtre de s‚lection : la concentration … prendre en compte pour pr‚venir l?‚mergence de r‚sistance (surtout pour des quinolones) * Pression de s‚lection pour les concentrations inf‚rieures … la CMI; CMI temps Concentration HypothŠses traditionnelles l?‚mergence de r‚sistance * CMP: le problŠme Dans un large inoculum, il est probable d?avoir une ou plusieurs sous-population … CMI plus ‚lev‚e que la majorit‚ du reste de la population … cause du taux spontan‚ des mutations (ex: 10-5) La sous population … CMI ‚lev‚e sera s‚lectionn‚e lorsque que la population mixte est expos‚e … des concentrations en antibiotique sup‚rieures … la CMI de la population sauvage (qui sera alors ‚radiqu‚e) mais inf‚rieures … la CMI de la sous-population ayant mis en place un m‚canisme de r‚sistance (qui sera la seule … pouvoir se d‚velopper) et qui sous la pression de s‚lection de l?antibiotique finira par devenir la population dominante * HypothŠses actuelles sur l?‚mergence de r‚sistance: dynamique des populations bact‚riennes * CPM (Concentration Pr‚ventive de Mutants) La CMP est la CMI de sous population(s), qui dans un large inoculum, a mis en place les premiers m‚canismes de r‚sistance En pratique, c?est la concentration pr‚venant le d‚veloppement d?un inoculum de taille 109_1010 La m‚thode de d‚termination est la mˆme que la CMI mais l?inoculum passe de 105 … 109 _1010 * Notion de fenˆtre de s‚lection CPM (Concentration pr‚ventive de mutants) (pour inhiber la croissance de la sous population ayant faut un premier saut mutationnel CMI (pour bloquer la population sauvage) Plasma concentrations Inhibition de toutes les Bie Croissance de la seule sous population mutante Croissance de toutes les Bie Fenˆtre de s‚lection des mutants * La fenˆtre de s‚lection La CMI et la CMP d‚finissent une gamme de concentrations nomm‚es fenˆtre de s‚lection C?est la diff‚rence entre la CPM et la CMI * Notion de fenˆtre de s‚lection * La fenˆtre de s‚lection La fenˆtre de s‚lection est la gamme des concentrations en antibiotique situ‚e entre la CMI et la CMP In vivo, la taille des inoculums ‚tant ‚lev‚es, on suspecte la pr‚sence de sous-populations … CMI plus ‚lev‚es et qui seront s‚lectionn‚e si l?exposition … l?antibiotique est suffisante pour ‚radiquer la population sauvage mais insuffisante pour ‚radiquer la sous population r‚sistante (m‚canisme de s‚lection de r‚sistance pour les quinolones) On doit fermer la fenˆtre de s‚lection en choisissant des sch‚mas posologiques garantissant des concentrations sup‚rieures aux CMP (souvent 5 fois la CMI) * Les mutants ne sont pas s‚lectionn‚s en dessous de la CMI et au dessus de la CPM * Les indices de pr‚vention des mutants Rapport MPC/CMI (d‚finit la largeur de la fenˆtre de s‚lection) De 4 … 8 pour les quinolones et pour le trim‚thoprime; 16 pour la doxycycline (MRSA); Temps pass‚ dans la fenˆtre de s‚lection (voir le chapitre consacr‚ … ce sujet) * Strat‚gies pour limiter le d‚veloppement de r‚sistance Rester au dessus des CPM Posologies ad‚quates (one shoot; AUC/MIC=250h) r‚duire l?‚tendue de la fenˆtre de s‚lection Objectif de d‚veloppement pour l?industrie. Traiter les animaux en m‚taphylaxie Faible inoculum avoir recours … des associations intelligentes d?antibiotiques (tuberculose chez l?homme). * Temps post-administration Concentration plasmatique Posologie pour que les concentrations plasmatiques libres passent au dessus de la CPM (toutes les bact‚ries seront ‚radicables) Strat‚gies pour limiter le d‚veloppement de r‚sistance: posologie ad‚quate * AUC/MIC > 125 h Garantir une AUC/MIC>125h veut dire que l?on garantit que la concentration plasmatique moyenne sur l?intervalle de dosage est 5 fois la CMI (voir la pr‚sentation des indices PKPD) Avec une AUIC/MIC de 250h (10 fois la CMI) on observe une ‚radication bact‚rienne trŠs rapide (environ 2 jours) Application v‚t‚rinaire: ®ÿone shootÿ¯ N‚cessit‚ de r‚viser les sch‚mas posologiques * Temps post-administration Concentration plasmatique Dose au dessus de la CPM Strat‚gies pour limiter le d‚veloppement de r‚sistance: fermer la fenˆtre de s‚lection CPM CMI Fermer la fenˆtre de s‚lection CPM~CMI Innovations pharmaceutiques pour avoir le plus petit rapport entre la CPM et la CMI; cela permet d?avoir des posologies plus faibles pour ‚radiquer les mutants * Valeurs des CMI & CPM pour les quinolones v‚t‚rinaires sur E coli et Staph aureus * Emergence vs. s‚lection de mutants r‚sistants par les quinlones Les quinolones peuvent favoriser l?‚mergence ou la s‚lection de mutants r‚sistants Pour de faibles concentrations (inf‚rieures aux CMI), ils augmentent le taux de mutations et partant l?apparition de mutants. Stimulation du systŠme SOS g‚nŠre des hypermutateurs Pour les concentrations situ‚es dans la fenˆtre de s‚lection, ils s‚lectionnent les mutants dej… pr‚sents * Objectifs th‚rapeutiques li‚s … la fenˆtre de s‚lection * Antibiotiques pour lesquels le concept de fenˆtre de s‚lection s?applique Quinolones Bˆta-lactams Macrolides T‚tracyclines * Days Log CFU/g of feces Ampicilline dans l?eau de boisson Inoculation de S liquefaciens From Duval-Yflah Y. et al. IAI 1980; 28 :981 R‚sistance … la colonisation par Serratia liquefaciens (m) multir‚sistante in vivo dans le tube digestif de souris … flore humaine [E. coli (o)]. vŠnement sans s‚lection S‚lection Amplification PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * Disease health Therapy Metaphylaxis (Control) Prophylaxis (pr‚vention) Growth promotion Strat‚gies pour limiter le d‚veloppement de r‚sistance: la m‚taphylaxie High Pathogen load Small No NA Antibiotic consumption PL Toutain Ecole V‚t‚rinaire Toulouse Ispa‹a 2010 * * curatif Strat‚gies pour limiter le d‚veloppement de r‚sistance: la m‚taphylaxie qui doit ˆtre vue comme un traitement trŠs pr‚coce m‚taphylaxie 10-8 10-8 10-8 pop sauvage sensible Pop sauvage Population de simple mutants pr‚sente au d‚but du traitement donc mutants s‚lectionnables Pas de mutants car l?inoculum initial au moment du traitement est trop faible pour avoir g‚n‚r‚ des mutants et donc pas de risque de s‚lection * Quelles sont les concentrations pour pr‚venir la s‚lection de bact‚ries … sensibilit‚ r‚duite? Beta-lactamines: Toujours rester au dessus de 4xMIC (mais 40-60% du temps >CMI pour efficacit‚) Aminoglycosides: Avoir au moins un pic de 8x MIC Fluoroquinolones: AUC/CMI > 200 et pic /CMI > 8

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Chaque ann‚e 1,24 million de personnes meurent dans des accidents

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* Chaque ann‚e 1,24 million de personnes meurent dans des accidents de la circulation … travers le monde. 92% des d‚cŠs par accident de la circulation

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* Chaque ann‚e 1,24 million de personnes meurent dans des accidents de la circulation … travers le monde. 92% des d‚cŠs par accident de la circulation surviennent dans des pays … revenu faible ou interm‚diaire. Commentez et argumentez Contr“le des connaissances Nø3 20/03/2013 * ECONOMIE DU DEVELOPPEMENT Partie 1, Chapitre 3 Farouk Alioua D‚partement des Sciences Humaines mars 2013 * Analyse compar‚e des th‚ories de d‚veloppement CHAPITRE 3 * l?‚conomie du d‚veloppement de l?aprŠs-guerre domin‚e par certaines visionsÿ: -Le modŠle de croissance par ‚tapes lin‚aires Les th‚ories et modŠles de changement structurel La th‚orie de la d‚pendance La r‚volution n‚oclassique du march‚ libre * I ? Les th‚ories par ‚tapes lin‚aires * Une des conditions est la mobilisation d?une ‚pargne int‚rieure et ‚trangŠre afin de g‚n‚rer un investissement suffisant … la croissance contexte inspirateur du plan Marshall Les ‚tapes de la croissance ‚conomique de Rostowÿ Philosophies et th‚ories lib‚rales de l?histoire * Selon Rostow, le d‚veloppement est un processus historique lin‚aire qui se d‚roule en suivant n‚cessairement cinq ‚tapes. En fait, Rostow a pr‚sent‚ un modŠle de croissance unique qu?aurait emprunt‚ tous les pays qui se sont industrialis‚. Dans son ouvrage The Stages Of Economic Grawth Rostow distingue cinq ‚tapes dans la croissance ‚conomique. 1.1. Les ‚tapes de la croissance selon Walter Rostow * Etape 1: La soci‚t‚ traditionnelle L?activit‚ est surtout agricole, et s?effectue dans le cadre familiale avec des techniques traditionnelles et une faible productivit‚. Etape 2: Les conditions pr‚alables au d‚collageÿ L?‚pargne et l?investissement se d‚veloppent, ce qui permet une augmentation de la production dans l?agriculture et l?industrie naissante. Etape 3: Le d‚collage ou le Tack-off Il s?agit de la phase d‚cisive d?une soci‚t‚ o— la croissance devient un ph‚nomŠne normal. Le Tack-off est rendu possible par une augmentation du taux d?investissement de 5 … 10% du revenu national, qui permet aux industries nouvelles de jouer un r“le moteur. * Etape 5: L?Šre de la consommation de masse Les besoins fondamentaux de la consommation sont satisfaits, et l?industrie a atteint sa maturit‚. Le secteur des services se d‚veloppe trŠs rapidement. Etape 4: La marche vers la maturit‚ Elle prolonge les effets du Tack-off, le taux d?investissement s?‚lŠve … 20% du revenu national, et donc les progrŠs techniques se g‚n‚ralisent. * Ces comportements vont permettre un accroissement de l?investissement et donc une acc‚l‚ration de la croissance de la production par tˆte. Passage de la stagnation (‚tape 1) L?essentiel de la dynamique du d‚veloppement, pour Rostow, tient … la modification des comportements d?‚pargne accumulation primitive (‚tape 2) financera le take-off (‚tape 3). La perspective de Rostow est fortement influenc‚e par l?analyse n‚oclassique de la croissance puisque l?‚pargne est le point de d‚part du processus de croissance et de d‚veloppement * * Le moteur de l?‚conomie dans notre soci‚t‚ de consommation est bas‚ sur l?innovation d?un c“t‚ et une logique sociale de diff‚rentiation de l?autre. Il existe diff‚rents types de capitalismes mais ils ont tous en commun la propri‚t‚ priv‚e (en majorit‚) des moyens de production. Le moteur de la croissance dans les ‚conomies de march‚ est r‚sum‚ dans le sch‚ma suivant : * des conditions ‚conomiques et techniques : possibilit‚ de d‚gager un surplus qui peut se transformer en ‚pargne, ce qui suppose une mon‚tisation de l?‚conomie, des progrŠs techniques mais aussi occasions d?investir (d‚veloppement des march‚s, de certains d‚bouch‚s, existence d?une main d uvre disponible)ÿ; des comportementsÿ: l?‚pargne de ce surplus n?est pas automatique ? voir les soci‚t‚s traditionnelles analys‚es par les anthropologuesÿ; qui plus est, la transformation de cette ‚pargne en capital n?est pas non plus naturelle ; ces transformations passent par l?‚mergence d?une nouvelle classe, une ‚lite ‚conomique … la culture plus ouverte … la logique capitaliste. Cette dynamique suppose une modificationÿ: * L?analyse de Rostow a eu une port‚e trŠs importante car elle mettait l?accent sur: l?industrialisation, la relation entre innovation et croissance, le lien entre croissance ‚conomique et d‚veloppement g‚n‚rale de la soci‚t‚. Elle a de plus inspir‚ de nombreuses politiques des ann‚es 1950 et des ann‚es 60. Cependant, plusieurs critiques ont ‚t‚ formul‚es vis-…-vis de la th‚orie de Rostow. Parmi les nombreuses critiques port‚es … Rostowÿ: * Certains affirmeront (Hirschman, 1988) que c?est au contraire la manifestation de la croissance et du d‚veloppementÿqui augmente les occasions d?investir et donc incitent … ‚pargner Une hausse du taux d?‚pargne dans les phases 2 et 3 n?entraŒne pas automatiquement la croissance et du d‚veloppementÿ; * Ainsi l?id‚e du d‚veloppement comme succession d?‚tapes pr‚d‚termin‚es a ‚t‚ trŠs critiqu‚e: Les marxistes (Bettelheim, 1961) consid‚raient cette th‚orie comme une justification, au nom du rattrapage, de la domination ext‚rieure (sous forme de prˆts)ÿ; Les marxistes proposent des strat‚gies de d‚veloppement auto-centr‚es pour s?arracher de la d‚pendance vis-…-vis des pays industrielsÿ; 2. D?autres critiques, insistent sur le caractŠre trop d‚terministe de la th‚orie de Rostow et pr‚fŠrent l?id‚e principale d?une entr‚e dans la croissance moderne plut“t que d?un enchaŒnement de relations causales par ‚tapes; Ils pointent le manque de fondements analytiques (Kuznets,1972) et empiriques (Gerschenkron, 1962) dans l?explication du passage d?une ‚tape … l?autre. * L?h‚t‚rog‚n‚it‚ des situations des pays autres que les pays d‚velopp‚s depuis la seconde guerre mondiale ; le succŠs fulgurant de certains pays asiatiques, et des pays ‚mergents ; la stagnation de la plupart des pays du continent africain ; la r‚cession des pays latino-am‚ricains. les critiques de l?approche en termes d?‚tapes ont ‚t‚ renforc‚es par: * Conscient des limites de son approche, Rostow, annonce qu?il a sous-estim‚ quatre facteurs essentiels qui ont jou‚ depuis la seconde guerre mondiale et qui distinguent ®ÿle processus de d‚veloppement enregistr‚ par le pass‚ et celui du monde contemporainÿ¯ (1988). * Facteurs positifsÿ: un r‚servoir plus grand de technologie non appliqu‚e et disponible pour la croissance rapide dans les PVDÿ; la disponibilit‚ d?une aide ‚trangŠre qui permet de d‚passer les insuffisances de l?accumulation primitive. Facteurs n‚gatifsÿ: les effets corrosifs de la Guerre Froideÿ; l?impact d?une croissance d‚mographique trŠs rapideÿ: ®ÿla plus marquante de ces diff‚rences, qui a entraŒn‚ un large ‚ventail de cons‚quences pathologiques, a ‚t‚ l?effort entrepris pour se moderniser avec une population croissant deux … trois fois plus vite qu?au 19Šme siŠcleÿ¯. * 1.2. Le modŠle de croissance de Harrod-Domar 1) l?‚pargne est fonction du revenu S = sY (a) 2) L?investissement est d‚fini comme la variation du stock de capital et peut ˆtre repr‚sent‚ par I = ?Y (b) Mais parce que le stock de capital Total K, entretient une relation directe au revenu national total Y, on peut repr‚senter par k qui est le ratio capital sur revenu K ?Y = k ou ?K/?Y = k En d‚finitive ?K = k?Y (c) 3) Finalement, parce que l?‚pargne nationale S doit ˆtre ‚gale au total de l?investissement I, on peut ‚crire cette ‚galit‚ comme suitÿ: S = I (d) I ? Les th‚ories par ‚tapes lin‚aires (suite) 1.1. Les ‚tapes de la croissance selon Walter Rostow * on peut dire que: S = sY = k?Y = ?K = I (e) Et nous avons donc, sY = k?Y (f) En divisant les deux parties de l?‚quation (f) par Y et ensuite par k on obtient la formule suivante : ?Y/Y = s/k (g) L?‚quation (g) est une version simplifi‚e de l?‚quation de Harrold-Domar qu?on trouve dans leur th‚orie de la croissanceÿ: le taux de croissance de revenu (?Y/Y) est d‚termin‚ conjointement par le ratio d?‚pargne national s et le ratio capital revenu k. * Ainsi pour croŒtre, une ‚conomie doit ‚pargner et investir une certaine proportion de son produit national. Plus elle ‚pargne et investit, plus elle croŒt. La contrainte au d‚veloppement, selon cette th‚orie, est le relatif niveau de formation de capital dans les pays pauvres. r“le donc de l?aide ‚trangŠre et de l?investissement direct ‚tranger. (th‚orie qui justifient l?id‚e d?un Plan Marshall pour les pays en d‚veloppement) * Limites et critiques des modŠles … ‚tapes lin‚aires Augmentation du taux national d?‚pargne est une condition n‚cessaire mais pas suffisante Le Plan Marshall fonctionna parce que l?Europe poss‚dait les conditions et les structures institutionnelles : march‚ mon‚taire, facilit‚s de transport, force de travail bien form‚, motivation des travailleurs, bureaucratie efficiente, Les modŠles font l?hypothŠse que ces conditions existent L?‚conomie des pays en d‚veloppement fait partie d?un systŠme international int‚gr‚ et complexe et les strat‚gies nationales sont invalid‚es dans un contexte mondial * Contr“le des connaissances Nø4 26/03/2013 Le modŠle de croissance de Harrod-Domar * I. Le modŠle de croissance par ‚tapes lin‚aires 1.1. Les ‚tapes de la croissance selon Walter Rostow 1.2. Le modŠle de croissance de Harrod-Domar II. Les th‚ories et modŠles de changement structurel III. Les th‚ories de la d‚pendance * II. Les th‚ories et ModŠles de changement structurel * ®Le problŠme central de la th‚orie ‚conomique est de comprendre le processus selon lequel une communaut‚ qui auparavant ‚conomisait et investissait 4 … 5 % de son revenu ou moins, se transforme en une ‚conomie o— l?‚pargne volontaire est de l?ordre de 12 … 15 % ou plus du revenu ¯ (Lewis). * les apports des th‚ories lin‚aires ont domin‚ la th‚orie ‚conomique du d‚veloppement (modŠle de Rostow,, modŠle d?Harrod-Domar, th‚orie des cercles vicieux de Nurkse). Le d‚veloppement ‚tait une question de capitaux, une question d?argent Aussi pour d‚marrer un processus de d‚veloppement, il faut financer ce passage, cette transition. Jusqu?aux ann‚es 70, * Alors on cherche l?appui de l?aide ext‚rieure n‚cessaire … l?‚tape de transition : c?est l?exemple plan Marshall Jusqu?… ce que l?‚pargne int‚rieure atteigne un niveau suffisant et que la croissance s?auto entretienne. Mais si un pays manque de ressources financiŠres? Jusqu?… quand? * A partir des ann‚es 70 des ‚tudes montraient une corr‚lation n‚gative entre flux financiers ext‚rieurs et ‚pargne int‚rieure dans les PVD: La raison est que l?augmentation de l?‚pargne ‚tait entrav‚e par de multiples facteurs. L?‚pargne n?‚tait pas toujours la variable qui croit automatiquement avec le revenu aprŠs une injection d?investissement comme le supposent les modŠles Keyn‚siens C?est au sein de ce d‚bat que sont ‚labor‚s les th‚ories du financement de la croissance dont la plus c‚lŠbre est le modŠle de Lewis * Lewis (1954) d‚crit une vision du d‚veloppement bas‚e sur un transfert de ressources de l?agriculture vers l?industrie. Deux flux fondamentaux de ressources … la base du processus de d‚veloppement : flux de main-d?oeuvre : de l?agriculture viennent les travailleurs n‚cessaires … l?industrie; flux de biens alimentaires : de l?agriculture vient ‚galement les biens alimentaires qui permettent … la force de travail non agricole de vivre. Cette approche voit le d‚veloppement ‚conomique comme la transformation progressive du secteur traditionnel en un secteur moderne, qui va au-del… de la transformation agriculture industrie mais est essentiellement construite sur cette base. * les profits sont … l?origine de l?‚pargne, de l?investissement et donc de la croissance : * ®Pratiquement toute l?‚pargne vient de ceux qui re‡oivent des hauts revenus ou des profits. L?‚pargne des travailleurs est trŠs faible. Les classes moyennes ‚pargnent peu, mais sans grande cons‚quence sur l?investissement productif : la plupart de ses membres ‚tant engag‚s dans la lutte permanente pour maintenir leur standing¯. * La classe des capitalistes industriels ou agricoles est la seule … investir de fa‡on productive. * Le d‚veloppement ne peut survenir que si la r‚partition des revenus se modifie en faveur des capitalistes (secteur priv‚ et public). b) Deux secteurs dans l?‚conomie: le secteur capitaliste et le secteur de subsistance * Le secteur de subsistance: (agriculture traditionnelle, secteur informel) * Productivit‚ des travailleurs trŠs faible comme les revenus * Productivit‚ marginale faible, ou mˆme nulle, inf‚rieure au revenu per‡u La productivit‚ marginale repr‚sente la variation de la production engendr‚e soit par l’ajout d’un travailleur suppl‚mentaire, soit par l’utilisation d’une unit‚ de capital suppl‚mentaire * PRODUCTIVIT C?est une mesure de l?efficacit‚ de la combinaison des facteurs de production. La PRODUCTIVIT MARGINALE repr‚sente la variation de la production engendr‚e soit par l’embauche d’un travailleur suppl‚mentaire, soit par l’utilisation d’une unit‚ de capital suppl‚mentaire. La PRODUCTIVIT DU CAPITAL mesure la relation entre la production et la quantit‚ de capital qui a permis la productionÿ: Pøÿ/ÿK La PRODUCTIVIT MARGINALE DU CAPITAL mesure le suppl‚ment de production obtenu avec une unit‚ suppl‚mentaire de capitalÿ: SUP(P) / SUP(K) La PRODUCTIVIT DU TRAVAIL mesure la relation entre la production et la quantit‚ de travail qui a permis la productionÿ: Pøÿ/ÿL La productivit‚ marginale du travail mesure le suppl‚ment de production obtenu avec une unit‚ suppl‚mentaire de travailÿ: SUP(P) / SUP(L) La PRODUCTIVIT APPARENTE mesure la variation observ‚e de la productivit‚ d?un facteur peut provenir soit d?une am‚lioration de l?efficacit‚ de ce facteur soit de l?am‚lioration de l?efficacit‚ ou de l?intensit‚ d?utilisation d?un autre facteur. Avant une ‚tude plus approfondie, la variation de la productivit‚ apparaŒt. * c) Offre illimit‚e de main d uvre: L?‚conomie dispose d?un exc‚dent de main d uvre correspondant au ch“mage d‚guis‚ du secteur de subsistance. Le secteur capitaliste moderne trouve dans le secteur de subsistance des r‚serves de travailleurs sans avoir … augmenter les salaires qui restent fixes. – Le modŠle abandonne le sch‚ma n‚oclassique o— l?offre de travail est limit‚e et salaire varie en fonction des conditions du march‚. D?autres facteurs garantissent l?abondance de main d uvre : l?entr‚e progressive des femmes sur le march‚ du travail, le ch“mage technologique, la croissance d‚mographique. * Le secteur moderne va progressivement absorber la main d uvre du secteur de subsistance, grƒce … un salaire un peu plus ‚lev‚, mais qui reste faible. L?embauche va d?abord durer tant que la productivit‚ marginale des travailleurs est inf‚rieure au salaire Le profit r‚alis‚ va ˆtre investi par les capitalistes, ce qui permettra d?accroŒtre la productivit‚ marginale et d?entamer une nouvelle phase d?embauche, jusqu?… l?‚galisation salaire productivit‚ marginale, et ainsi de suite. A la fin du processus, toute la main d uvre en exc‚dent sera absorb‚ par le secteur capitaliste, les revenus et les salaires vont alors s?‚lever dans le secteur de subsistance o— la main d uvre n?est plus abondante et ‚galement dans le secteur moderne. Le processus de d‚veloppement commence … b‚n‚ficier aux travailleurs, mais les profits vont voir leur part baisser, l?investissement et la croissance vont ralentir d) Le d‚veloppement consiste dans le renforcement du secteur moderne et la r‚duction progressive du secteur jug‚ archa‹que * Le modŠle de Lewis met l?accent sur la part croissante des profits dans le revenu national, li‚e … la progression du secteur capitaliste. Le taux d?investissement va s?‚lever pour permettre une croissance rapide. * Le modŠle suppose que le taux de transfert du travail et de cr‚ation d?emplois dans le secteur moderne sont proportionnels au taux d?accumulation du capital dans ce secteur. Plus rapide est l?accumulation du capital, plus le taux de croissance du secteur moderne ‚lev‚ et plus rapide est le taux de cr‚ation de nouveaux emplois. CEPENDANT on constate que les profits capitalistes sont r‚investis dans des technologies plus sophistiqu‚es et plus ‚conomes en travail. HypothŠse de surplus de main-d’?uvre dans les zones rurales et de plein-emploi dans le secteur urbain (march‚ du travail urbain concurrentiel). Les ‚conomistes du d‚veloppement aujourd?hui s?accordent sur le fait que cette hypothŠse est trŠs largement invalid‚e en pratique. Les limites du modŠle de Lewis * Critiques du modŠle (suite) . Par ailleurs, Lewis fait l?hypothŠse que les profits capitalistes sont r‚investis dans l?‚conomie locale et qu?ils ne seront pas r‚investis … l?‚tranger. * I. Le modŠle de croissance par ‚tapes lin‚aires II. Les th‚ories et modŠles de changement structurel III. Les th‚ories de la d‚pendance * 3.1 Prebisch et la CEPAL 3.2 change in‚gal et d‚connexion: Samir Amin 3.3 Le d‚veloppement d‚pendant: Cardoso 3.4. Critiques des th‚ories de la d‚pendance 3.5. Impacts et influence des th‚ories de la d‚pendance III ? Les th‚ories de la d‚pendance (d‚but ann‚es 70) * ? Principaux th‚oriciens originaires de l?Am‚rique latine (Dos Santos, Sunkel, Furtado, Frank, Cardoso), puis de l?Afrique (Samir Amin) ? Deux principales sources intellectuelles : le n‚o-marxisme et les analyses de la CEPAL Origines et sources intellectuelles 3.1. Prebisch et la CEPAL Origines et sources intellectuelles (suite) * A. N‚o-marxisme ? Adopte le point de vue de la p‚riph‚rie plut“t que celui du centre ? Marxisme orthodoxe pr‚conise r‚volution bourgeoise, suivie d?une r‚volution socialiste; le n‚o-marxiste considŠre que le ®ÿTiers-Mondeÿ¯ est m–r pour la r‚volution socialiste ? Marxisme considŠre le prol‚tariat industriel comme la classe r‚volutionnaire; n‚o-marxisme met l?accent sur les paysans. ? N‚o-marxisme acad‚mique aussi d‚velopp‚ aux USA par Paul Baran dans les ann‚es 1950 : d‚montre l?interrelation entre l?industrialisation britannique et la d‚sindustrialisation de l?Inde Origines et sources intellectuelles (suite) * Prebisch conteste la validit‚ de la th‚orie classique du commerce international et attribue le sous-d‚veloppement de l?Am‚rique latine … des causes principalement externes : ? libre-‚change entraŒne une division internationale du travail qui confine l?Am‚rique latine … un r“le d?exportateur de produits primaires ? les exportateurs de produits primaires subissent une constante d‚gradation des termes de l?‚change CEPAL: Commission ‚conomique de l?ONU pour l?Am‚rique latine, dirig‚e de 1948-62 par Ra—l Prebisch, ‚conomiste argentin B. Ra—l Prebisch et la CEPAL Que dit la th‚orie classique du commerce international ? * Les avantages comparatifs (A. Smith, D. Ricardo) ? Tout pays peut augmenter son revenu grƒce au commerce ? Chaque pays a avantage … se sp‚cialiser dans l?exportation des marchandises qu?il produit au meilleur co–t relatif ? Le libre-‚change produit une division internationale du travail favorable … tous puisqu?elle permet : ? de produire plus de biens en utilisant au maximum les facteurs de production ? accŠs … un march‚ plus vaste ? producteurs de biens export‚s peuvent obtenir prix plus ‚lev‚s que sur march‚ national ? biens import‚s le sont … meilleur co–t que s?ils ‚taient produits sur le march‚ national ? D‚veloppement technique fera baisser le prix des produits industriels, au profit des producteurs de matiŠres premiŠres Prebisch: La d‚t‚rioration des termes de l?‚change * Termes de l?‚change : ? rapport de l?indice des prix des produits export‚s par un pays … l?indice des prix des produits import‚s; ? permet de comparer l?‚volution du pouvoir d?achat que procurent les biens export‚s par un pays ? Selon les ‚tudes de Prebisch, les termes de l?‚change des pays exportateurs de matiŠres premiŠres se sont constamment d‚t‚rior‚s face … ceux des pays industrialis‚s ? Prebisch affirme que les pays en d‚veloppement sont victimes d?un ®‚change in‚gal¯ La d‚t‚rioration des termes de l?‚change: Explications avanc‚es * 1. Les prix des produits manufacturiers des pays d‚velopp‚s demeurent ‚lev‚s parce que : ? des monopoles r‚ussissent … maintenir prix ‚lev‚s ? les syndicats arrivent … obtenir des hausses de salaires 2. Producteurs des PED ne sont pas organis‚s et sont en comp‚tition, contribuant … la hausse constante de l?offre et … la baisse des prix des matiŠres premiŠres. 3. lasticit‚ de la demande pour les produits manufacturiers est plus grande que celle pour les produits agricoles … Loi de Engels : Quand le revenu augmente, la part consacr‚e … l’alimentation et … l’habillement diminue et celle consacr‚e aux autres d‚penses augmente Propositions ‚conomiques de Prebisch et de la CEPAL * ? Acc‚l‚rer l?industrialisation de l?Am‚rique latine et r‚duire la d‚pendance envers les matiŠres premiŠres ? Industrialisation acc‚l‚r‚e visant … produire localement les biens import‚s (®industrialisation par substitution aux importations¯) ? Intervention active de l?‚tat pour coordonner les investissements et prot‚ger les industries nouvelles ? Int‚gration r‚gionale pour pallier … l?‚troitesse des march‚s Nationaux ? ? la fin des ann‚es 50, programme mis en ?uvre par Argentine, Br‚sil, Colombie, P‚rou et influence strat‚gies des nouveaux ‚tats du Tiers-Monde mergence de la th‚orie de la d‚pendance * ? ApparaŒt en Am‚rique latine … la fin des ann‚es 50- d‚but 60 ? Audience importante aux tats-Unis et en Europe ? Se construit en r‚action …: ? Th‚ories de la modernisation: s?y oppose violemment sur plusieurs aspects ? Th‚ories de la CEPAL: ? adopte plusieurs de ses notions: ‚change in‚gal, d‚t‚rioration des termes de l?‚change ? d‚nonce son ‚conomisme et son discours modernisateur ? constate l?‚chec de son application Th‚orie de la d‚pendance Principaux thŠmes * ? Le sous-d‚veloppement des pays de la p‚riph‚rie est le produit du d‚veloppement du Centre ? La division internationale du travail maintient les pays sous-d‚velopp‚s dans un ‚change In‚gal ? Les efforts d?industrialisation du Tiers-Monde augmentent sa d‚pendance car son ‚conomie est extravertie * 3.1 Prebisch et la CEPAL 3.2 change in‚gal et d‚connexion: Samir Amin 3.3 Le d‚veloppement d‚pendant: Cardoso 3.4. Critiques des th‚ories de la d‚pendance 3.5. Impacts et influence des th‚ories de la d‚pendance III ? Les th‚ories de la d‚pendance (d‚but ann‚es 70) 3.2 change in‚gal et d‚connexion (Samir Amin) 1/ Critique des th‚ories de la modernisation * ? Les explications en termes de ®cercles vicieux de la pauvret‚¯ (Nurske) sont erron‚es, pas toujours vraies, pas toujours v‚rifi‚es ?il existe une ‚pargne dans les PED, mais elle est gaspill‚e, export‚e, employ‚e … des d‚penses improductives par les ‚lites. ? Pays sous-d‚velopp‚s ne sont pas une image des pays d‚velopp‚s … un stade ant‚rieur ?ils font partie d?un systŠme mondial qui a forg‚ leur structure ? Facteurs culturels ou religieux ne peuvent pas expliquer le sous-d‚veloppement ?aucun pays n?est fonciŠrement ®traditionnel¯ et/ou ®ÿarcha‹queÿ¯ * ? Commerce international = ‚change in‚gal ? secteur ®traditionnel¯ du Tiers-Monde contribue au maintien de bas salaires 2/ change in‚gal et critique de l?‚conomie classique ? conomie classique et th‚ories de la modernisation pŠchent par ®‚conomisme¯ ? l?int‚gration de la p‚riph‚rie dans le systŠme capitaliste mondial a ‚t‚ un processus politique ? commerce international est, depuis d‚but du 20Šme S., domin‚ par des monopoles, qui faussent les ‚changes ? Les faits d‚mentent les pr‚dictions de l?‚conomie. En effet il existe ? ‚carts croissants entre Centre et p‚riph‚rie ? d‚gradation constante des termes de l?‚change * Le Centre a cr‚‚ le secteur exportateur de la p‚riph‚rie en fonction de ses propres besoins. 3/ ®Le d‚veloppement du sous-d‚veloppement¯ Samir Amin d‚finit le sous-d‚veloppement par trois critŠres Structurels: 3. Domination externe In‚galit‚ de productivit‚ entre divers secteurs 2. D‚sarticulation des systŠmes ‚conomiques La p‚riph‚rie est beaucoup plus d‚pendante de ses ‚changes avec le Centre que l?inverse. * La P‚riph‚rie doit constamment augmenter ses exportations pour: ? rembourser ses prˆts ? payer ses importations, en hausse constante: ? produits alimentaires, pour classes urbaines ? biens d?‚quipements, pour industrialisation ? produits de luxe, pour privil‚gi‚s occidentalis‚s 3/ ®Le d‚veloppement du sous-d‚veloppement¯ (suite) SystŠme mondial contient deux types de capitalisme: ? celui du Centre, dynamique et auto-centr‚ ? celui de la p‚riph‚rie, capitalisme ®bloqu‚¯ * 4) La solution ? LA DECONNEXION SystŠme ‚conomique auto-reproducteur doit ˆtre mis en place: liaisons entre secteurs des biens de consommation et d?‚quipement N‚cessite planification ‚conomique par l?tat Impose remise en cause de la division internationale du travail Pr‚f‚rable que cette rupture avec le march‚ mondial se fasse dans de grands espaces * 3.1 Prebisch et la CEPAL 3.2 change in‚gal et d‚connexion: Samir Amin 3.3 Le d‚veloppement d‚pendant: Cardoso 3.4. Critiques des th‚ories de la d‚pendance 3.5. Impacts et influence des th‚ories de la d‚pendance III ? Les th‚ories de la d‚pendance (d‚but ann‚es 70) 3.3. Le ®d‚veloppement d‚pendant¯ * Cardoso Fernando Henrique constate que la situation du Br‚sil ne correspond pas aux modŠles des th‚ories de la d‚pendance : ? l?‚conomie n?est pas uniquement concentr‚e sur le secteur des matiŠres premiŠres ? une structure industrielle produisant pour le march‚ local est en place (ex : industrie automobile) Une certaine forme de d‚veloppement a donc eu lieu, mais il s?agit d?un ® d‚veloppement d‚pendant ¯ Cardoso: le ®d‚veloppement d‚pendant¯ * S‚rieuses limitations ? Le Br‚sil a recours … des technologies ‚trangŠres, intensives en capital, peu cr‚atrices d?emplois ? La distribution des revenus est trŠs in‚galitaire ? la production est ax‚e sur biens de consommation de luxe ? L?endettement ‚tranger pose des problŠmes de d‚pendance ? conomie conduite par une alliance entre Etat militaire, capital ‚tranger et bourgeoisie locale ? Structure industrielle largement domin‚e par des multinationales, qui contr“lent deux ‚l‚ments-cl‚s : finances et technologie * 3.1 Prebisch et la CEPAL 3.2 change in‚gal et d‚connexion: Samir Amin 3.3 Le d‚veloppement d‚pendant: Cardoso 3.4 Critiques des th‚ories de la d‚pendance 3.5. Impacts et influence des th‚ories de la d‚pendance III ? Les th‚ories de la d‚pendance (d‚but ann‚es 70) 3.4. Critiques des th‚ories de la d‚pendance * ? D‚nonc‚es comme trop id‚ologiques; ? N‚gligence des dynamiques internes, en particulier de l?autonomie d?action de l?tat et de la bourgeoisie locale; ? Trop pessimistes: ne peuvent expliquer pourquoi des exportateurs de matiŠres premiŠres (ex: Canada) et des pays du Tiers-Monde (Cor‚e, Singapour) se sont d‚velopp‚s; ? Propositions politiques vagues et qui ont ‚chou‚ lorsque mises en application. Ex: substitution des importations en Am‚rique latine et d‚veloppement autonome en Tanzanie * 3.1 Prebisch et la CEPAL 3.2 change in‚gal et d‚connexion: Samir Amin 3.3 Le d‚veloppement d‚pendant: Cardoso 3.4 Critiques des th‚ories de la d‚pendance 3.5. Impacts et influence des th‚ories de la d‚pendance III ? Les th‚ories de la d‚pendance (d‚but ann‚es 70) 3.5. Impacts et influence des th‚ories de la d‚pendance * Elles ont contribu‚ … plusieurs d‚bats importants: ? relation entre commerce international et d‚veloppement ? distinction des notions de croissance et de d‚veloppement ? notion de systŠme capitaliste mondial Ces th‚ories ont d‚montr‚ l?importance des facteurs externes responsables du sous-d‚veloppement Ils ont constitu‚ le fondement des revendications du Tiers-Monde dans les ann‚es 1960-70 ? cr‚ation de la CNUCED ( Conf‚rence des NU pour le Commerce et le D‚veloppement) ? cartels de producteurs de matiŠres premiŠres ? Nouvel ordre ‚conomique international … l?ONU Th‚orie du systŠme-monde (Immanuel Wallerstein ) * Les principales influences de Wallerstein : ?Karl Marx: Il utilise plusieurs de ses concepts; les applique au systŠme mondial plut“t que dans l?espace national; ? Fernand Braudel : historien fran‡ais qui a d‚crit le d‚veloppement des grands r‚seaux d?‚changes ‚conomiques de l?Europe du 15-18Šme S. Il s?inspire de sa m‚thode d?‚tude de la longue dur‚e; ? Les th‚ories de la d‚pendance: Il ‚labore les notions de systŠme mondial et de centre-p‚riph‚rie * ? L?histoire a connu deux types de systŠmes-monde ? empire-monde: systŠme politique unique ? ‚conomie-monde: inclut plusieurs systŠmes politiques 1) Concept de systŠme-monde ? Unit‚ d?analyse appropri‚e pour comprendre les relations de pouvoir au sein du systŠme international est l?‚conomie-monde capitaliste ®les seules vrais systŠmes sociaux sont, d?une part, les ‚conomies de subsistance relativement ‚troites [] et, d?autre part, les systŠmes-mondes¯ (Wallerstein, 1980) * La place d?un pays n?est pas d‚finitive: certains pays de la p‚riph‚rie peuvent ®graduer¯ en recevant industries d‚localis‚es (ex: Br‚sil, Cor‚e, Afrique du Sud) 2) Dynamique de l?‚conomie-monde capitaliste ? Tendance … l?expansion g‚ographique ? stimul‚e par quˆte d?accumulation de capital ? a graduellement int‚gr‚ l?ensemble de la planŠte, en attribuant … chaque zone un r“le sp‚cifique ? Polarisation r‚gionale et hi‚rarchie ? Centre: capitaux; technologie; structures ‚tatiques fortes ? P‚riph‚rie: ‚conomie d‚pendante; ‚tats faibles ? Semi-p‚riph‚rie: zone ®tampon¯ importante * ? Polarisation de l?‚conomie-monde renforc‚e par l?‚change in‚gal ? fond‚ sur la capacit‚ du centre … utiliser le pouvoir politique et la force pour fixer les prix des transactions ? Comme Amin, Wallerstein insiste sur les relations entre les instances ‚conomiques et politiques ? capitalistes ont utilis‚ les appareils d?Etat pour prot‚ger march‚s domestiques, accroŒtre profits et expansion ? Le capitalisme connaŒt des cycles, qui sont facteurs de transformation du systŠme ? crises stimulent d‚localisations 2) Dynamique de l?‚conomie-monde capitaliste (suite) * ? Wallerstein pr“ne l?abandon de strat‚gies nationales pour un mouvement socialiste mondial 3) L?‚conomie-monde capitaliste depuis 1945 ? SystŠme a su dompter forces anti-syst‚miques ? mouvements ouvriers du Centre ? ‚lites nationalistes de la p‚riph‚rie ? crise ‚cologique menace le systŠme ? conomie-monde est entr‚e en crise depuis le d‚but des ann‚es 1970 ? explique vague de d‚localisations vers semi-p‚riph‚rie ? marque d‚but de l?effondrement du systŠme. Il n?y n?aura bient“t plus de travailleurs ruraux … bon march‚ … int‚grer pour r‚duire co–ts de production Comparaison: th‚ories de la d‚pendance vs th‚orie du systŠme-monde * ? Th‚orie du systŠme monde moins d‚terministe: reconnaŒt que la place des pays n?est pas fig‚e ? Th‚orie du systŠme-monde souvent assimil‚e aux th‚ories de la d‚pendance, partagent de nombreux thŠmes ? Unit‚ d?analyse = systŠme capitaliste historique, plut“t que r‚gions d‚pendantes ? Pour Wallerstein, le capitalisme forme un systŠme unique; pas de distinction entre capitalismes du centre et de la p‚riph‚rie

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Elements of Design Sight Distances (p.3-1 so that 3-18 ) Be able

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* 3: Elements of Design Sight Distances (p.3-1 so that 3-18 ) Be able so that define in addition so that use the stopping sight distance equation Be able

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Elements of Design Sight Distances (p.3-1 so that 3-18 ) Be able so that define in addition to use the stopping sight distance equation Be able so that explain the difference between stopping sight distance in addition to decision sight distance Be able so that tell the components of passing sight distance Be able so that explain the difference between passing sight distance defined by AASHTO in addition to passing sight distance defined by MUTCD that is used so that locate no passing zones Know how so that measure these sight distances Objectives: * 3.2 Sight Distance A driver?s ability so that see ahead is of the utmost importance in the safe in addition to efficient operation of a vehicle on a highway. Diverse types of drivers, from 16 years old so that senior drivers (Read a statement in the book about a comparison alongside train control) At minimum, must provide sight distance of sufficient length so that safely stop when an unexpected object appears on the traveled way On 2-lane 2-way highways, provide sufficient sight distance so that enable drivers so that occupy the opposing traffic lane in consideration of passing overtaken vehicles without hazard ON 2-lane 2-way highways, NO PASSING zone must be clearly defined 3.2.1 General Considerations: * Aspects of Sight Distance discussed in this section (3.2.1) Sight distances needed in consideration of stopping – applicable on all highways Sight distances needed in consideration of decisions at complex locations Sight distances needed in consideration of the passing of overtaken vehicles ? applicable only so that two-lane two-way highways Sight distance is the length of the roadway ahead that is visible so that the driver. * 3.2.2 Stopping Sight Distance (p.3-2) Stopping sight distance = sufficiently long sight distance in consideration of a vehicle traveling at or near the design speed so that stop before reaching a stationary object t = 2.5 sec (can be 1.0 so that 1.5 sec on urban streets) ? = 11.2 ft/s2 Alongside this ?/g = about 0.35 (90th percentile values) AASHTO Greenbook 1994 had this figure ? longitudinal friction factor vs. speed. This was replaced by ?/g beginning the 2001 edition of the Greenbook. (3-2) * Deriving the braking distance formula * Deriving the braking distance formula (continued) Forces acting on this free body is at equilibrium: W*sinr -W*f*cosr = W*a/g a is unknown. We want so that use the known values (initial speed u, in addition to distance x) so that determine a. We assume first the vehicle accelerated from speed 0 so that u. x = «at2 & u = at Now t = u/a. Plug in this in the RHS of x x = «a t2 = «a(u2/a2) x = («)(u2/a) Solve in consideration of a: Now, we get: It?s deceleration, so add -. * Deriving the braking distance formula (continued) The braking distance is a horizontal distance (do you know why we use a horizontal distance?) while x is the distance along the slope; therefore, Db = x * cosr Š x = Db/cosr Once you know this, you can easily follow the derivation in the text. Go so that page 64. Substitute Db in addition to x in the first equation in the previous slide so that get Db. Eq. 3.18 * Table 3-1 in addition to 3-2 SSD Values SSDs shown here are in consideration of passenger cars. Truck drivers? eye heights are much higher in addition to they can see further. Hence, SSDs in consideration of just trucks are not used. * 3.2.3 Decision Sight Distance DSDs are a bit longer than SSDs so that allow the driver so that take unexpected actions. Usually PIEV is longer than regular cases in consideration of SSDs. DSDs are used: At locations of complex decision making Where information is difficult so that perceive Where unexpected or unusual maneuvers are required Like interchanges, merge areas, so many signs clustered at one point, etc. (alongside a lot of visual ?noise?) If DSDs cannot be provided, supplement alongside traffic control devices (signs, markers, etc.) Assumptions in consideration of computation in addition to measurement: 3.5 ft eye height in addition to 2 ft object height. * Table 3-3. DSDs In consideration of A in addition to B In consideration of C, D, in addition to E (Different formulas are used.) * 3.2.4 Passing Sight Distance Criteria in consideration of Design The overtaken vehicle travels at uniform speed. The passing vehicle has reduced speed in addition to trails the overtaken vehicle as it enters a passing section. When the passing section is reached, the passing driver needs a short period of time so that perceive the clear passing section in addition to so that react so that start his or her maneuver. Passing is accomplished under what may be termed a delayed start in addition to a hurried return in the face of opposing traffic. The passing vehicle accelerates during the maneuver, in addition to its average speed during the occupancy of the left lane is 10 mph higher than that of the overtaken vehicle. When the passing vehicle returns so that its lane, there is a suitable clearance length between it in addition to an oncoming vehicle in the other lane. * How the min. passing sight distance in consideration of 2-lane 2-way highways is determined. d1 ? Distance traversed during perception in addition to reaction time IN ADDITION TO during the initial acceleration so that the point of encroachment on the left lane. d2 ? Distance traveled while the passing vehicle occupies the left lane. d3 ? Distance between the passing vehicle at the end of its maneuver in addition to the opposing vehicle d4 ? Distance traversed by an opposing vehicle in consideration of two-thirds of the time the passing vehicle occupies the left lane, or 2/3 of d2. * Elements of PSD d3 = Clearance length, empirical d4 = Distance traversed by an opposing vehicle = d1 = Initial maneuver distance d2 = Distance while passing vehicle occupies left lane 2/3 of d2 Note: m value changed from 10 mph (GB2004) so that 12 mph (GB2011). m = 12 mph, used so that be 10 mph * Exhibit 3-5 Elements of PSD This exhibit 3-5 was deleted in GB2011. * PSD Design Values (GB2004) Exhibit 3-6 Exhibit 3-7 These exhibits were omitted from GB2011. PSD Design Values (GB2011), p.3-9 * These values are those of PSD from MUTCD. Comparison between SSD & PSD * * MUTCD on Passing Sight Distance (p.3-12) MUTCD 2009 Table 3-5 GB2011: Min Passing Zone Lengths so that be included in Traffic Operational Analyses, p.3-14 * * MUTCD on Passing Sight Distance (cont) MUTCD 2009

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ÿ 2012 SSTAGE RTI STAR Award Teasley Middle School Cherokee County Amy

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2012 SSTAGE RTI STAR Award Teasley Middle School Cherokee County Amy Graham, Donna Bertram, Judy Withey Assistant Principal, RTI Coach, Academic Coa

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ÿ 2012 SSTAGE RTI STAR Award Teasley Middle School Cherokee County Amy Graham, Donna Bertram, Judy Withey Assistant Principal, RTI Coach, Academic Coach EQ: How does the RTI process address individual student needs? Creative Approaches so that the RTI Process in a Title I Middle School Teasley at a glance 71% are exclusively on Tier 1 Tier 4 includes district feeder self-contained programs TIER 1 Tier 1 Data Analysis Individual Scheduling Universal Screenings Benchmarks (Quarterly) Differentiation Academic Double Dip Learning Focused School S.W.A.G Anti-bullying Program Teacher As Advisor Classroom Guidance Behavior Discipline System TIER 1 PROGRAMS Family & Student Portal USATestPrep Georgia On-line Assessment System Successmaker Math 6 + 1 Writing Traits While these are research based programs used in Cherokee County, there are many other programs a school may implement. Behavior Discipline Chart ?Point Sheet? is a part of each TMS student?s agenda. RTI TERMINOLOGY Created by Cherokee County School District TIER 2 (13% of population) RTI Tuesday POINT Plans Academic in addition to Behavioral Interventions Tier 2 Interventions Reading Paired Reading Peer Tutoring Repeated Reading Math Peer Tutoring Small Group Tutoring Behavior Success Contract Check-n-Connect Rewards/Consequences TIER 3 (1% of population) Weekly Progress Monitoring Quarterly Parent Meetings More Intensive Interventions Consult SLP in addition to School Psychologist Tier 3 Interventions Reading Repeated Reading Math One-on-One Tutoring Behavior Continue Check-n-Connect Rewards/Consequences Mentor TIER 2 & 3 PROGRAMS Study Island Timez Attack SOLO Literacy Support READ 180 Wilson Reading Check-n-Connect Attendance Panels While these are research based programs used in Cherokee County, there are many other programs a school may implement Attendance Rewards & Interventions Quarterly in addition to End-of-Year Rewards Letters sent home at 2, 5, 7, 10 in addition to 12 absences TMS Attendance Panel TADRA Requirements Mentors Assigned RTI Teasley Style Scheduling Academic Double Dose Saturday School EXP/Club Extreme Title I Summer School BELL SCHEDULE Quarterly Rotation 1st 1234567 2nd 2134576 3rd 7634521 4th 6734512 DOUBLE DOSE Remediation vs. Acceleration Reading/Math Success Math/ELA/Science Enrichment TEACHER SUPPORT Professional Development Teacher-so that-Teacher Observation RTI Coach County-level Training Professional Learning Communities CCGPS Curriculum Technology Double Planning Period CCSD RTI PORTAL Easy click access so that current data in consideration of students being served through the RTI process Created by Cherokee County School District RTI PORTAL Demographics Student Name ID Number School in addition to Attendance History Academic History Services Currently Provided What educational services are already being provided? Standardized Test Scores at a glance Assessment History Strengths, Weaknesses, in addition to Academic Concerns Meeting History Specific Concerns in addition to Goals Academic Concerns Listing of behaviors observed by teachers BEHAVIORAL CONCERNS Created by Cherokee County School District Georgia Department of Education in collaboration alongside the Student Support Team Association in consideration of Georgia Educators RTI Star Award Winners: Georgia Pyramid of Interventions EQ: HOW DOES THE RTI PROCESS ADDRESS INDIVIDUAL STUDENT NEEDS? Georgia Department of Education in collaboration alongside the Student Support Team Association in consideration of Georgia Educators RTI Star Award Winners: Georgia Pyramid of Interventions THANK YOU!

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2015 Pearson Education, Inc. 6 Circular Motion, Orbits, in addition

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? 2015 Pearson Education, Inc. 6 Circular Motion, Orbits, in addition so that GravityEssential Question: How can we describe motion in a circle, including

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? 2015 Pearson Education, Inc. 6 Circular Motion, Orbits, in addition to GravityEssential Question: How can we describe motion in a circle, including orbital motion under the influence of a gravitational force. 2015 Pearson Education, Inc.An object moving in a circle at a constant speed experiences acceleration directed toward the center of the circlea has same direction as ?vvf-viWhat does this mean in consideration of the direction of the net force? 6 Preview Looking Back: Centripetal Acceleration? 2015 Pearson Education, Inc. 6 Preview Stop so that ThinkA softball pitcher is throwing a pitch. At the instant shown, the ball is moving in a circular arc at a steady speed. At this instant, the acceleration isDirected up.Directed down.Directed left.Directed right.Zero.? 2015 Pearson Education, Inc.Preview Question 6.1For uniform circular motion, the accelerationIs parallel so that the velocity. Is directed toward the center of the circle.Is larger in consideration of a larger orbit at the same speed.Is always due so that gravity.Is always negative.? 2015 Pearson Education, Inc.Preview Question 6.2When a car turns a corner on a level road, which force provides the necessary centripetal acceleration?Friction Normal forceGravityTensionAir resistance? 2015 Pearson Education, Inc. Preview Question 6.3A passenger on a carnival ride rides in a car that spins in a horizontal circle as shown at right. At the instant shown, which arrow gives the direction of the net force on one of the riders 2015 Pearson Education, Inc.Preview Question 6.4 Newton?s law of gravity describes the gravitational force betweenThe earth in addition to the moon. The earth in addition to the sun. The sun in addition to the planets.A person in addition to the earth.All of the above.? 2015 Pearson Education, Inc.Section 6.1 Uniform Circular Motion? 2015 Pearson Education, Inc. Velocity in addition to Acceleration in Uniform Circular MotionSpeed of a particle in uniform circular motion is constantVelocity is not constantdirection of the motion is always changing? 2015 Pearson Education, Inc.QuickCheck 6.2A ball at the end of a string is being swung in a horizontal circle. The ball is accelerating becauseThe speed is changing.The direction is changing.The speed in addition to the direction are changing.The ball is not accelerating.? 2015 Pearson Education, Inc.Conceptual Example 6.1 Velocity in addition to acceleration in uniform circular motionA car is turning a tight corner at a constant speed. A top view of the motion is shown in FIGURE 6.2. The velocity vector in consideration of the car points so that the east at the instant shown. What is the direction of the acceleration 2015 Pearson Education, Inc. Conceptual Example 6.1 Velocity in addition to acceleration in uniform circular motion (cont.)Curve that the car is following is a segment of a circleUniform circular motionAcceleration directed toward the center of circleSouthAcceleration due so that change in direction, not change in speedThink about your experience in a car: if you turn the wheel so that the right?as the driver of this car is doing?your car then changes its motion toward the right, in the direction of the center of the circle? 2015 Pearson Education, Inc.QuickCheck 6.3A ball at the end of a string is being swung in a horizontal circle. What is the direction of the acceleration of the ball?Tangent so that the circle, in the direction of the ball?s motionToward the center of the circle? 2015 Pearson Education, Inc.Period, Frequency, in addition to SpeedPeriod, T: time it takes object so that go around a circle one timeFrequency, f: number of revolutions per second:SI unit of frequency is inverse seconds, or s?1? 2015 Pearson Education, Inc. Period, Frequency, in addition to Speed? 2015 Pearson Education, Inc.Example 6.2 Spinning some tunesAn audio CD has a diameter of 120 mm in addition to spins at up so that 540 rpm.When a CD is spinning at its maximum rate, how much time is required in consideration of one revolution?If a speck of dust rides on the outside edge of the disk, how fast is it moving?What is the acceleration 2015 Pearson Education, Inc.Example 6.2 Spinning some tunesprepare Before we get started, we need so that do some unit conversions. The diameter of a CD is given as 120 mm, which is 0.12 m. The radius is 0.060 m. The frequency is given in rpm (revolutions per minute); we need so that convert this so that s?1:? 2015 Pearson Education, Inc. Example 6.2 Spinning some tunes (cont.)solve The time in consideration of one revolution is the period. This is given by Equation 6.2:The dust speck is moving in a circle of radius 0.0060 m at a frequency of 9.0 s?1. Find the speed alongside modified velocity formula:Use modified acceleration formula so that find the acceleration:? 2015 Pearson Education, Inc.Example Problem ? Partner BreakoutA hard drive disk rotates at 7200 rpm. The disk has a diameter of 5.1 in (13 cm). What is the speed of a point 6.0 cm from the center axle? What is the acceleration of this point on the disk? ? 2015 Pearson Education, Inc.Section 6.2 Dynamics of Uniform Circular Motion? 2015 Pearson Education, Inc. Dynamics of Uniform Circular MotionObjects traveling around in uniform circular motion are acceleratingCan also extend this so that Newton?s 2nd law:? 2015 Pearson Education, Inc.Dynamics of Uniform Circular Motion? 2015 Pearson Education, Inc.QuickCheck 6.4A ball at the end of a string is being swung in a horizontal circle. What force is producing the centripetal acceleration of the ball?GravityAir resistanceNormal forceTension in the string? 2015 Pearson Education, Inc. QuickCheck 6.5A ball at the end of a string is being swung in a horizontal circle. What is the direction of the net force on the ball?Tangent so that the circleToward the center of the circleThere is no net force.? 2015 Pearson Education, Inc.QuickCheck 6.6 An ice hockey puck is tied by a string so that a stake in the ice. The puck is then swung in a circle. What force is producing the centripetal acceleration of the puck?GravityAir resistanceFrictionNormal forceTension in the string? 2015 Pearson Education, Inc.QuickCheck 6.7A coin is rotating on a turntable; it moves without sliding. At the instant shown in the figure, which arrow gives the direction of the coin?s velocity 2015 Pearson Education, Inc. QuickCheck 6.8A coin is rotating on a turntable; it moves without sliding. At the instant shown in the figure, which arrow gives the direction of the frictional force on the coin 2015 Pearson Education, Inc.QuickCheck 6.9A coin is rotating on a turntable; it moves without sliding. At the instant shown, suppose the frictional force disappeared. In what direction would the coin move 2015 Pearson Education, Inc.Engineers design curves, on roads so that be segments of circlesDips in addition to peaks, tooRadius depends on expected speeds, other factorsA car is moving at a constant speed in addition to goes into a dip in the road. At the very bottom of the dip, is the normal force of the road on the car greater than, less than, or equal so that the car?s weight?Conceptual Example 6.4 Forces on a car, part I? 2015 Pearson Education, Inc. Car is acceleratingMoving at constant speedBut direction is changingBottom of the dipCenter of circular path is directly above itAcceleration vector points straight upFree-body diagram identifies two forces acting on carNormal force, pointing upwardWeight, pointing downwardWhich is larger: n or w?Conceptual Example 6.4 Forces on a car, part I (cont.)? 2015 Pearson Education, Inc.A car is turning a corner at a constant speed, following a segment of a circle. What force provides the necessary centripetal acceleration?Conceptual Example 6.5 Forces on a car, part II? 2015 Pearson Education, Inc.Conceptual Example 6.5 Forces on a car, part II (cont.)If you were driving on a car on a frictionless road, such as a very icy road, would you be able so that turn a corner? So what force allows you so that turn? ? 2015 Pearson Education, Inc. QuickCheck 6.1A hollow tube lies flat on a table. A ball is shot through the tube. As the ball emerges from the other end, which path does it follow 2015 Pearson Education, Inc.Problem-Solving Strategy 6.1 Circular Dynamics Problems? 2015 Pearson Education, Inc.Text: p. 165Example Problem ? Partner BreakoutIn the track in addition to field event known as the hammer throw, an athlete spins a heavy mass in a circle at the end of a chain. Once the mass gets moving at a good clip, the athlete lets go of the chain. The mass flies off in a parabolic arc; the winner is the one who gets the maximum distance. In consideration of male athletes, the ?hammer? is a mass of 7.3 kg at the end of a 1.2-m chain. A world-class thrower can get the hammer up so that a speed of 29 m/s. If an athlete swings the mass in a horizontal circle centered on the handle he uses so that hold the chain, what is the tension in the chain? ? 2015 Pearson Education, Inc. Problem-Solving Strategy 6.1 Circular Dynamics Problems (cont.)? 2015 Pearson Education, Inc.Text: p. 165What is the maximum speed alongside which a 1500 kg car can make a turn around a curve of radius 20 m on a level (unbanked) road without sliding (ms = 1.0)? (This radius turn is about what you might expect at a major intersection in a city.) Example 6.7 Finding the maximum speed so that turn a corner? 2015 Pearson Education, Inc.Car moves along circular arc at constant speedUniform circular motionDirection of net force (from static friction) must point in the direction of the accelerationStatic friction force points toward the center of the circlex-axis toward the center of the circley-axis perpendicular so that the plane of motionExample 6.7 Finding the maximum speed so that turn a corner? 2015 Pearson Education, Inc. Example 6.7 Finding the maximum speed so that turn a corner (cont.) Newton?s second law in the y-direction is so that n = w = mg. ? 2015 Pearson Education, Inc.Example 6.7 Finding the maximum speed so that turn a corner (cont.)Max speed is reached when the static friction force reaches its maximum value fs max = msmgAnything greater than this will cause the car so that slideMax speed occurs at the maximum value of the force of static friction, or when ? 2015 Pearson Education, Inc.Example 6.7 Finding the maximum speed so that turn a corner (cont.)Using the known value of fs max, we findRearranging, we getFor rubber tires on pavement, ms = 1.0. We then have? 2015 Pearson Education, Inc. Example 6.7 Finding the maximum speed so that turn a corner (cont.)Does the mass of the car matter?What other variables would affect max velocity 2015 Pearson Education, Inc.Example 6.8 Finding speed on a banked turnA curve on a racetrack of radius 70 m is banked at a 15ø angle. At what speed can a car take this curve without assistance from friction 2015 Pearson Education, Inc.No friction actingOnly two forces: normal force in addition to car?s weightConstruct the free-body diagramDraw normal force perpendicular so that the road?s surfaceCar is tilted but still moving in a horizontal circleDon?t tilt axesChoose the x-axis so that be horizontal in addition to pointing toward the center of the circle.Example 6.8 Finding speed on a banked turn (cont.)? 2015 Pearson Education, Inc. Since keeping original axes in place, must split normal forceNo frictionnx = n sin q is component of force toward center of circleThis part of normal force causes it so that turn the cornerExample 6.8 Finding speed on a banked turn (cont.)? 2015 Pearson Education, Inc.From the y-equation,Substituting this into the x-equation in addition to solving in consideration of ? giveOnly at this exact speed can the turn be negotiated without reliance on friction forces.Example 6.8 Finding speed on a banked turn (cont.)? 2015 Pearson Education, Inc.Example Problem ? Partner BreakoutA level curve on a country road has a radius of 150 m. What is the maximum speed at which this curve can be safely negotiated on a rainy day when the coefficient of friction between the tires on a car in addition to the road is 0.40? ? 2015 Pearson Education, Inc. Maximum Walking SpeedIn a walking gait, your body is in circular motion as you pivot on your forward foot.? 2015 Pearson Education, Inc.Maximum Walking SpeedNewton?s second law in consideration of the x-axis isSetting n = 0 in Newton?s second law givesWhat does this say about the maximum walking speed in consideration of different people 2015 Pearson Education, Inc.Section 6.3 Apparent Forces in Circular Motion? 2015 Pearson Education, Inc. Centrifugal Force?If you are a passenger in a car that turns a corner quickly, the force of the car door pushing inward toward the center of the curve causes you so that turn the cornerYour body is trying so that move ahead in a straight line as outside forces (the door) act so that turn you in a circleA centrifugal force will never appear on a free-body diagram in addition to never be included in Newton?s laws.? 2015 Pearson Education, Inc.Apparent Weight in Circular Motion? 2015 Pearson Education, Inc.Apparent Weight in Circular MotionForce felt is the apparent weightMagnitude of contact force that supports you When passenger on roller coaster is at bottom of the loop:The net force points upward, so n > wHer apparent weight is wapp= n, so her apparent weight is greater than her true weight? 2015 Pearson Education, Inc. Apparent Weight in Circular MotionNewton?s second law in consideration of the passenger at the bottom of the circle is From this equation, the passenger?s apparent weight isHer apparent weight at the bottom is greater than her true weight, w? 2015 Pearson Education, Inc.Apparent Weight in Circular MotionNewton?s second law in consideration of the passenger at the top of the circle is Note that wx is now positive because the x-axis is directed downward. We can solve in consideration of the passenger?s apparent weight:If v is sufficiently large, her apparent weight can exceed the true weight (so wapp could be less than, equal so that, or greater than w)? 2015 Pearson Education, Inc.Apparent Weight in Circular MotionAs the car goes slower there comes a point where n becomes zero:The speed in consideration of which n = 0 is called the critical speed vc. Because in consideration of n so that be zero we must have , the critical speed isThe critical speed is the slowest speed at which the car can complete the circle? 2015 Pearson Education, Inc. Example Problem ? Partner BreakoutA handful of professional skaters have taken a skateboard through an inverted loop in a full pipe. In consideration of a typical pipe alongside a diameter 14 feet, what is the minimum speed the skater must have at the very top of the loop? ? 2015 Pearson Education, Inc.? 2015 Pearson Education, Inc.A physics textbook swings back in addition to forth as a pendulum. Which is the correct free-body diagram when the book is at the bottom in addition to moving so that the right? QuickCheck 6.10A car that?s out of gas coasts over the top of a hill at a steady 20 m/s. Assume air resistance is negligible. Which free-body diagram describes the car at this instant?QuickCheck 6.11? 2015 Pearson Education, Inc. QuickCheck 6.12A roller coaster car does a loop-the-loop. Which of the free-body diagrams shows the forces on the car at the top of the loop? Rolling friction can be neglected.? 2015 Pearson Education, Inc.Centrifuges? 2015 Pearson Education, Inc.Try It Yourself: Human CentrifugeIf you spin your arm rapidly in a vertical circle, the motion will produce an effect like that in a centrifuge. The motion will assist outbound blood flow in your arteries in addition to retard inbound blood flow in your veins. There will be a buildup of fluid in your hand that you will be able so that see (in addition to feel!) quite easily.? 2015 Pearson Education, Inc. An 18-cm-diameter ultracentrifuge produces an extraordinarily large centripetal acceleration of 250,000g, where g is the free-fall acceleration due so that gravity.What is its frequency in rpm?What is the apparent weight of a sample alongside a mass of 0.0030 kg?Example 6.10 Analyzing the ultracentrifuge? 2015 Pearson Education, Inc.Example 6.10 Analyzing the ultracentrifuge? 2015 Pearson Education, Inc.Example 6.10 Analyzing the ultracentrifuge (cont.)Converting so that rpm, we findAcceleration is so high that every force is negligible except in consideration of the force that provides the centripetal acceleration. The net force is simply equal so that the inward force, which is also the sample?s apparent weight:The 3 gram sample has an effective weight of about 1700 pounds!? 2015 Pearson Education, Inc. Example 6.10 Analyzing the ultracentrifuge (cont.)Note: acceleration is 250,000gApparent weight is 250,000 times actual weight? 2015 Pearson Education, Inc.A coin sits on a turntable as the table steadily rotates counterclockwise. What force or forces act in the plane of the turntable? QuickCheck 6.13? 2015 Pearson Education, Inc.A coin sits on a turntable as the table steadily rotates counterclockwise. The free-body diagrams below show the coin from behind, moving away from you. Which is the correct diagram? QuickCheck 6.14? 2015 Pearson Education, Inc. A car turns a corner on a banked road. Which of the diagrams could be the car?s free-body diagram? QuickCheck 6.15? 2015 Pearson Education, Inc.Example Problem ? Partner BreakoutA car of mass 1500 kg goes over a hill at a speed of 20 m/s. The shape of the hill is approximately circular, alongside a radius of 60 m, as in the figure. When the car is at the highest point of the hill,What is the force of gravity on the car? What is the normal force of the road on the car at this point 2015 Pearson Education, Inc.Orbital MotionForce of gravity on a projectile is directed toward the center of the earth? 2015 Pearson Education, Inc. Section 6.4 Circular Orbits in addition to Weightlessness? 2015 Pearson Education, Inc.Orbital MotionIf the launch speed of a projectile is sufficiently large, there comes a point at which the curve of the trajectory in addition to the curve of the earth are parallelSuch a closed trajectory is called an orbitAn orbiting projectile is in free fall? 2015 Pearson Education, Inc.Orbital MotionThe force of gravity is the force that causes the centripetal acceleration of an orbiting object:An object moving in a circle of radius r at speed vorbit will have this centripetal acceleration ifThat is, if an object moves parallel so that the surface alongside the speed? 2015 Pearson Education, Inc. Orbital MotionThe orbital speed of a projectile just skimming the surface of a smooth, airless earth isWe can use vorbit so that calculate the period of the satellite?s orbit:? 2015 Pearson Education, Inc.Weightlessness in OrbitAstronauts in addition to their spacecraft are in free fall.? 2015 Pearson Education, Inc.QuickCheck 6.19Astronauts on the International Space Station are weightless becauseThere?s no gravity in outer space.The net force on them is zero.The centrifugal force balances the gravitational force. g is very small, although not zero.They are in free fall.? 2015 Pearson Education, Inc. The Orbit of the MoonThe moon, like all satellites, is simply ?falling? around the earth.If we use the distance so that the moon, r = 3.84 ? 108 m, in:we get a period of approximately 11 hours instead of one monthThis is because the magnitude of the force of gravity, in addition to thus the size of g, decreases alongside increasing distance from the earthSo this calculation doesn?t work!? 2015 Pearson Education, Inc.Example Problem ? Partner BreakoutPhobos is one of two small moons that orbit Mars. Phobos is a very small moon, in addition to has correspondingly small gravity?it varies, but a typical value is about 6 mm/s2. Phobos isn?t quite round, but it has an average radius of about 11 km. What would be the orbital speed around Phobos, assuming it was round alongside gravity in addition to radius as noted? ? 2015 Pearson Education, Inc.Section 6.5 Newton?s Law of Gravity? 2015 Pearson Education, Inc. Gravity Obeys an Inverse-Square LawGravity is a universal force that affects all objects in the universeNewton proposed that the force of gravity has the following properties:The force is inversely proportional so that the square of the distance between the objects.The force is directly proportional so that the product of the masses of the two objects.? 2015 Pearson Education, Inc.Gravity Obeys an Inverse-Square LawNewton?s law of gravity is an inverse-square lawDoubling the distance between two masses causes the force between them so that decrease by a factor of 4G is the gravitational constant6.67 x 10-11 N?m2/kg2? 2015 Pearson Education, Inc.Conceptual Example 6.11 Varying gravitational forceThe gravitational force between two giant lead spheres is 0.010 N when the centers of the spheres are 20 m apart. What is the distance between their centers when the gravitational force between them is 0.160 N 2015 Pearson Education, Inc. Conceptual Example 6.11 Varying gravitational force? 2015 Pearson Education, Inc.Example 6.12 Gravitational force between two peopleYou are seated in your physics class next so that another student 0.60 m away. Estimate the magnitude of the gravitational force between you. Assume that you each have a mass of 65 kg.We will model each of you as a sphere. This is not a particularly good model, but it will do in consideration of making an estimate. We will take the 0.60 m as the distance between your centers.? 2015 Pearson Education, Inc.Example 6.12 Gravitational force between two people (cont.)solve The gravitational force is given by:Do you feel this force 2015 Pearson Education, Inc. The force of Planet Y on Planet X is ___ the magnitude of .One quarterOne halfThe same asTwiceFour timesQuickCheck 6.16? 2015 Pearson Education, Inc.2MMPlanet XPlanet YQuickCheck 6.17The gravitational force between two asteroids is 1,000,000 N. What will the force be if the distance between the asteroids is doubled? 250,000 N 500,000 N1,000,000 N2,000,000 N4,000,000 N? 2015 Pearson Education, Inc.If you traveled so that another planet, your mass would be the same but your weight would vary. The weight of a mass m on the moon is given byUsing Newton?s law of gravity weight is given bySince these are two expressions in consideration of the same force, they are equal andGravity on Other Worlds? 2015 Pearson Education, Inc. Gravity on Other WorldsIf we use values in consideration of the mass in addition to the radius of the moon, we compute gmoon = 1.62 m/s2A 70-kg astronaut wearing an 80-kg spacesuit would weigh more than 330 lb on the earth but only 54 lb on the moon? 2015 Pearson Education, Inc.QuickCheck 6.18Planet X has free-fall acceleration 8 m/s2 at the surface. Planet Y has twice the mass in addition to twice the radius of planet X. On Planet Y g = 2 m/s2 g = 4 m/s2 g = 8 m/s2 g = 16 m/s2 g = 32 m/s2? 2015 Pearson Education, Inc.QuickCheck 6.22A 60-kg person stands on each of the following planets. On which planet is his or her weight the greatest 2015 Pearson Education, Inc. Example 6.14 Finding the speed so that orbit DeimosMars has two moons, each much smaller than the earth?s moon. The smaller of these two bodies, Deimos, isn?t quite spherical, but we can model it as a sphere of radius 6.3 km. Its mass is 1.8 ? 1015 kg. At what speed would a projectile move in a very low orbit around Deimos 2015 Pearson Education, Inc.Example 6.14 Finding the speed so that orbit Deimos (cont.)solve The free-fall acceleration at the surface of Deimos is small:? 2015 Pearson Education, Inc.Example 6.14 Finding the speed so that orbit Deimos (cont.)Given this, we can calculate the orbital speed:assess This is quite slow. Alongside a good jump, you could easily launch yourself into an orbit around Deimos!? 2015 Pearson Education, Inc. Example Problem ? Partner BreakoutA typical bowling ball is spherical, weighs 16 pounds, in addition to has a diameter of 8.5 in. Suppose two bowling balls are right next so that each other in the rack. What is the gravitational force between the two?magnitude in addition to direction? ? 2015 Pearson Education, Inc.Section 6.6 Gravity in addition to Orbits? 2015 Pearson Education, Inc.Gravity in addition to OrbitsNewton?s second law tells us that FM on m = ma, where FM on m is the gravitational force of the large body on the satellite in addition to a is the satellite?s acceleration.Because it?s moving in a circular orbit, Newton?s second law gives? 2015 Pearson Education, Inc. Gravity in addition to OrbitsA satellite must have this specific speed in order so that maintain a circular orbit of radius r about the larger mass M? 2015 Pearson Education, Inc.Gravity in addition to OrbitsFor a planet orbiting the sun, the period T is the time so that complete one full orbit. The relationship among speed, radius, in addition to period is the same as in consideration of any circular motion: v = 2?r/TCombining this alongside the value of v in consideration of a circular orbit givesIf we square both sides in addition to rearrange, we find the period of a satellite:? 2015 Pearson Education, Inc.QuickCheck 6.20Two satellites have circular orbits alongside the same radius. Which has a higher speed?The one alongside more mass.The one alongside less mass.They have the same speed.? 2015 Pearson Education, Inc. QuickCheck 6.21Two identical satellites have different circular orbits. Which has a higher speed?The one in the larger orbitThe one in the smaller orbitThey have the same speed.? 2015 Pearson Education, Inc.QuickCheck 6.23A satellite orbits the earth. A Space Shuttle crew is sent so that boost the satellite into a higher orbit. Which of these quantities increases?SpeedAngular speedPeriodCentripetal accelerationGravitational force of the earth? 2015 Pearson Education, Inc.Example 6.15 Locating a geostationary satelliteCommunication satellites appear so that ?hover? over one point on the earth?s equator. A satellite that appears so that remain stationary as the earth rotates is said so that be in a geostationary orbit. What is the radius of the orbit of such a satellite 2015 Pearson Education, Inc. Example 6.15 Locating a geostationary satelliteFor the satellite so that remain stationary alongside respect so that the earth, the satellite?s orbital period must be 24 hours; in seconds this is T = 8.64 ? 104 s.? 2015 Pearson Education, Inc.Example 6.15 Locating a geostationary satellite (cont.)Solve in consideration of radius of orbitMass at the center of the orbit is the earth:? 2015 Pearson Education, Inc.Gravity on a Grand ScaleNo matter how far apart two objects may be, there is a gravitational attraction between themGalaxies are held together by gravityAll of the stars in a galaxy are different distances from the galaxy?s center, in addition to so orbit alongside different periods? 2015 Pearson Education, Inc. Example Problem ? Partner BreakoutPhobos is the closer of Mars?s two small moons, orbiting at 9400 km from the center of Mars, a planet of mass 6.4 ? 1023 kg. What is Phobos?s orbital period? How does this compare so that the length of the Martian day, which is just shy of 25 hours? ? 2015 Pearson Education, Inc.

To Write this Article, I had done research in Universidade Federal do Acre BR.

2007 Pearson Prentice Hall This work is protected by United States

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? 2007 Pearson Prentice Hall This work is protected by United States copyright laws in addition so that is provided solely in consideration of the use of i

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? 2007 Pearson Prentice Hall This work is protected by United States copyright laws in addition to is provided solely in consideration of the use of instructors in teaching their courses in addition to assessing student learning. Dissemination or sale of any part of this work (including on the World Wide Web) will destroy the integrity of the work in addition to is not permitted. The work in addition to materials from it should never be made available so that students except by instructors using the accompanying text in their classes. All recipients of this work are expected so that abide by these restrictions in addition to so that honor the intended pedagogical purposes in addition to the needs of other instructors who rely on these materials. Figures 2 College Physics, 6th Edition Wilson / Buffa / Lou Figure 2-1 Distance ? total path length In driving so that State University from Hometown, one student may take the shortest route in addition to travel a distance of 81 km (50 mi). Another student takes a longer route in order so that visit a friend in Podunk before returning so that school. The longer trip is in two segments, but the distance traveled is the total length, 97 km + 48 km = 145 km (90 mi). Figure 2-4 Distance (scalar) in addition to displacement (vector) (a) The distance (straight-line path) between the student in addition to the physics lab is 8.0 m in addition to is a scalar quantity. (b) So that indicate displacement, x1 in addition to x2 specify the initial in addition to final positions, respectively. The displacement is then ?x = x2 ? x1 = 9.0 m ? 1.0 m = +8.0 m ? that is, 8.0 m in the positive x-direction. Learn by Drawing 2-1 Cartesian Coordinates in addition to One-Dimensional Displacement A two-dimensional Cartesian coordinate system. A displacement vector d locates a point (x, y). (b) In consideration of one-dimensional, or straight-line, motion, it is convenient so that orient one of the coordinate axes along the direction of motion. Figure 2-6 Uniform linear motion ? constant velocity In uniform linear motion, an object travels at a constant velocity, covering the same distance in equal time intervals. (a) Here, a car travels 50 km each hour. (b) An x-versus-t plot is a straight line, since equal displacements are covered in equal times. The numerical value of the slope of the line is equal so that the magnitude of the velocity, in addition to the sign of the slope gives its direction. (The average velocity equals the instantaneous velocity in this case. Why?) Figure 2-7 Position-versus-time graph in consideration of an object in uniform motion in the negative x-direction A straight line on an x-versus-t plot alongside a negative slope indicates uniform motion in the negative x-direction. Note that the object?s location changes at a constant rate. At t = 4.0 h the object is at x = 0. How would the graph look if the motion continues in consideration of t > 4.0 h? Figure 2-8 Position-versus-time graph in consideration of an object in non-uniform linear motion In consideration of a non-uniform velocity, an x-versus-t plot is a curved line. The slope of the line between two points is the average velocity between those positions, in addition to the instantaneous velocity is the slope of a line tangent so that the curve at any point. Five tangent lines are shown, alongside the intervals in consideration of ?x/?t in the fifth. Can you describe the object?s motion in words? Figure 2-9 Acceleration ? the time rate of change of velocity Since velocity is a vector quantity, alongside magnitude in addition to direction, an acceleration can occur when there is (a) a change in magnitude, but not direction; (b) a change in direction, but not magnitude; or (c) a change in both magnitude in addition to direction. Learn by Drawing 2-2 Signs of Velocity in addition to Acceleration Figure 2-10 Velocity-versus-time graphs in consideration of motions alongside constant accelerations Figure 2-11 Away they go! Ex. 2.7 Two riders on dune buggies sit 10 m apart on a long straight track, facing in opposite directions. Starting at the same time, both riders accelerate at a costant rate of 2.0 m/s2. How far apart will the dune buggies be at the end of 3.0s? Figure 2-12 Vehicle stopping distance Example 2.8 The stopping distance of a vehicle is an important factor in road safety. This distance depends on the initial velocity (vo) in addition to the braking capacity which produces the deceleration, a., assumed so that be constant. Express the stopping distance x in terms of these quantities. Figure 2-13 v-versus-t graphs, one more time In the straight-line plot in consideration of a constant acceleration, the area under the curve is equal so that x, the distance covered. (b) If v0 is not zero, the distance is still given by the area under the curve, here divided into two parts, areas A1 in addition to A2 . Figure 2-14 Free fall in addition to air resistance (a) When dropped simultaneously from the same height, a feather falls more slowly than a coin, because of air resistance. But when both objects are dropped in an evacuated container alongside a good partial vacuum, where air resistance is negligible, the feather in addition to the coin both have the same constant acceleration. Figure 2-16 Free fall up in addition to down Ex. 2.11 A worker on a scaffold in front of a billboard throws a ball straight up. The ball has an initial speed of 11.2 m/s, when it leaves the worker?s hand. (a) What is the maximum height the ball reaches relative so that the top of the billboard? (b) How long does it take the ball so that reach this height? (c) What is the position of the ball at t = 2.0 s? Figure 2-19 Speed versus velocity 13. An insect crawls along the edge of a rectangular swimming pool of length 27 m in addition to width 21 m. If it crawls from corner A so that corner B in 30 min, (a) what is its average speed in addition to (b) what is its average velocity? Figure 2-20 Position versus time 14. A plot of position versus time is shown in 4Fig. 2.20 in consideration of an object in linear motion. (a) What are the average velocities in consideration of the segments AB, BC, CD, DE, EF, FG, in addition to BG? (b) State whether the motion is uniform or nonuniform in each case. (c) What is the instantaneous velocity at point D?ÿÿ Figure 2-21 Position versus time 15. In demonstrating a dance step, a person moves in one dimension, as shown in 6Fig. 2.21. What are (a) the average speed in addition to (b) the average velocity in consideration of each phase of the motion? (c) What are the instantaneous velocities at 2.5 s, 4.5 s, in addition to 6.0 s? (d) What is the average velocity in consideration of the interval between in addition to [Hint: Recall that the overall displacement is the displacement between the starting point in addition to the ending point.]ÿÿ Figure 2-22 When in addition to where do they meet? 22. Two runners approaching each other on a straight track have constant speeds of in addition to respectively, when they are 100 m apart (6Fig. 2.22). How long will it take in consideration of the runners so that meet, in addition to at what position will they meet if they maintain these speeds?ÿÿ Figure 2-21 Description of motion Figure 2-23 Velocity versus time 33. What is the acceleration in consideration of each graph segment in 6Fig. 2.23? Describe the motion of the object over the total time interval.ÿÿ Figure 2-23 Velocity versus time Figure 2-24 Hit the professor Figure 2-25 From where did it come? Figure 2-27. A tie race 77. A car in addition to a motorcycle start from rest at the same time on a straight track, but the motorcycle is 25.0 m behind the car (4Fig. 2.26). The car accelerates at a uniform rate of in addition to the motorcycle at a uniform rate of (a) How much time elapses before the motorcycle overtakes the car? (b) How far will each have traveled during that time? (c) How far ahead of the car will the motorcycle be 2.00 s later? (Both vehicles are still accelerating.)ÿÿ Figure 2-28 Down she comes

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.MANAGING CLASSROOM BEHAVIOURMETA-ANALYSISeach strand of a rope

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.MANAGING CLASSROOM BEHAVIOURMETA-ANALYSISeach strand of a rope contributes so that the strength of that ropebut the rope is stronger than any individ

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.MANAGING CLASSROOM BEHAVIOURMETA-ANALYSISeach strand of a rope contributes so that the strength of that ropebut the rope is stronger than any individual strand.META-ANALYSISSimilarly, when a particular finding is obtained again in addition to again under a variety of conditions, we are strongly confident that there exists a general principle of behaviour.The results of individual studies, no matter how well conducted, are unlikely so that provide answers so that questions of general importance. META-ANALYSISMETA-ANALYSIS is a quantitative tool in consideration of comparing or combining results across a range of similar studies.INDIVIDUAL STUDY the unit of analysis looks at the response of individual subjects.META-ANALYSIS the unit of analysis is the results of individual studies.A clear distinction is drawn between ?authoritarian? in addition to ?authoritative? classroom management styles, alongside the latter being more effective in improving social in addition to academic outcomes in consideration of students. Classroom behaviour.It is now recognised that behaviour management skills in themselves are a necessary but not sufficient condition in consideration of creating an effective learning environment. John Hattie.that it is excellence in teachers that makes the greatest difference. John HattieInvestigated three types of teachersEXPERTACCOMPLISHEDNOVICEEXPERT have deeper representations about teaching in addition to learning in addition to because of these deeper representations can be much more responsive so that students. EXPERT. Expert teachers are more effective scanners of classroom behaviour, make greater reference so that the language of instruction in addition to learning of studentsACCOMPLISHED whereas accomplished teachers concentrate more on what the teacher is saying in addition to doing so that the class (Hattie, 2003). NOVICE.novices concentrate more on student behaviour (Hattie, 2003). EXPERTHattie found that expert teachers showed high respect in consideration of students.The manner used by the teacher so that treat the students, respect them as learners in addition to people, in addition to demonstrate care in addition to commitment in consideration of them are attributes of expert teachers. 5 strategies Effective teaching in addition to learning requires more than an orderly classroom. Traynor, in a review of the literature, identified five strategies used by teachers in classroom management:coercive laissez-faire task oriented authoritative intrinsic (Traynor, 2002). 2 most effectiveAUTHORATATIVEINTRINSIC Authoratative Using the authoritative strategy, the teacher manages student behavior by enforcing a specific in addition to reasonable set of classroom rules (Collette & Chiapetta, 1989 as cited by Traynor, 2002).Intrinsicthe intrinsic strategy in consideration of classroom order is so that increase student control over himself/herselfLewis 2001Unnecessarily harsh in addition to punitive disciplinary practices against students create a climate that contributes so that school violence. This issue is little recognized in addition to scarcely researched (Hyman & Snook, 2000 as cited in Lewis, 2001) Lewis 2001publication is a report of the perceptions of over 3,500 Australian school students. This study:demonstrates empirically that in the view of these students, their teachers are characterized by two distinct discipline styles. Coercive disciplineRelational-based disciplineCoercive discipline?coercive? discipline comprised punishment in addition to aggression Relational-based discipline comprising discussion, hints, recognition, involvement in addition to punishment Relationship-basedStudents who receive more Relationship-based discipline are less disrupted when teachers deal alongside their misbehavior in addition to generally act more responsibly in that teacher?s class. Coercive disciplinethe impact of Coercive discipline appears so that be more student distraction from work in addition to less responsibility (Lewis, 2001 as cited in Lewis et al., 2005).Caring classroompromotes positve student behaviour. Caring classroomsIdentified four aspects of teacher behaviour: 1. MODELLING CARING RELATIONSHIPS2. ESTABLISHING DIALOGUES CHARACTERISED BY A SEARCH IN CONSIDERATION OF COMMON UNDERSTNDING3. RECOGNISING POSITIVE BEHAVIOURS4. PROVIDING PRACTISE IN ADDITION TO OPPORTUNITIES SO THAT CARE IN CONSIDERATION OF OTHERSREFERENCEWilkinson, J. & Meiers, M. (2007). Managing student behaviour in the classroom. NSWIT Research Digest, 2008(1). Retrieved May13th, 2010, from nswteachers.nsw.edu.au

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Shaving Putting on make-up Reading a map Reaching behind you so that

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* Shaving Putting on make-up Reading a map Reaching behind you so that spank kids Not using a seatbelt Driving under the influence Driving at an unsaf

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* Shaving Putting on make-up Reading a map Reaching behind you so that spank kids Not using a seatbelt Driving under the influence Driving at an unsafe speed Failing so that stop or yield Unsafe passing of another vehicle Tailgating Not using blinkers Others? * *Though perhaps in a different category, eating when driving in addition to using cell phones can compromise your response time by distracting you in addition to by removing one hand from the steering wheel. Road rage is driving under the influence of too much anger. Provoked by: Feeling endangered by someone else?s driving (another driver cuts you off or tailgates you). Resentment at being forced so that slow down Righteous indignation at someone who breaks traffic rules Anger at someone taking out their road rage on you Therapy in consideration of road rage: Take a deep breath in addition to just let it go! * Poor visibility Night time driving (Fatality rates/mile are 4 times higher at night.) Dust storms Rain storms Windshield wipers not effective Poor road conditions Slippery surfaces from weather Road not properly maintained Improper vehicle maintenance Inadequate brakes Worn tread on tires Hoses, belts Inadequate acceleration Headlight(s) out Other? * Daytime running lights (Headlights that are on whenever vehicle is running) Lap/shoulder safety belts Reduce risk of moderate-so that-fatal injuries by approximately 50%. Air bags in consideration of driver & passenger Combined alongside lap/shoulder belts, they reduce risk of fatality by another 10%. Side impact airbags Ability so that disengage airbags Child safety seats Note: Children in child seats should not be placed in the front seat of cars Anti-lock brakes Safety cages built into the vehicle framework If buying a new car, ask about side-impact collision data. Other? * When driving on a road that is new so that you: You eyes tend so that scan the road from left so that right which is an excellent driving habit. We tend not so that scan when in familiar territory. How closely can you safely follow another car? We tend so that follow based on how much of the road we can see A long hood causes us so that follow at a greater distance (since you have so that look over the hood so that see the street). Drivers alongside shorter hoods tend so that follow more closely Use the 2 or 4 second rule Good driving conditions, keep a 2 second distance behind Poor driving conditions, keep a 4 second distance behind * Golf Carts Gator Vehicles Toro Vehicles * Did you know that defensive driving applies NOT ONLY so that licensed vehicles such as cars in addition to trucks but also so that unlicensed vehicles such as golf carts in addition to Gators? * Carts roll easier Carts always operate near pedestrians Carts run silently Other motor vehicles have the right-of-way * Center of gravity is lower than most vehicles In a collision ? the cart ALWAYS loses! * Applies so that ALL operators of service carts on campus-electric or gas powered ALL users must have a current/valid driver?s license in possession Drivers must be 18 years of age or older All drivers must be trained in cart operation ALL employees operating carts must comply alongside all traffic laws Employees are responsible in consideration of understanding in addition to complying alongside the manufacturer?s operating recommendations * * * * Always check behind the vehicle before backing No more occupants that the number of seats Keep hands in addition to feet inside the vehicle Drive slow Avoid steep grades * Conduct a visual check of the cart before driving Do the brakes work? Check in consideration of correct tire pressure * Check in consideration of obstacles or pedestrians around the vehicle Adjust mirrors Check lights & turn signals Be sure everything is properly stored * Obey ALL traffic signs Do not exceed cart weight capacity Sudden stops or changes in direction may result in loss of control Keep hands in addition to feet inside at all times when cart is moving Avoid tipping over ? drive straight up or down a slope Always remain seated Slow down before in addition to during turns Reduce speed, use extra care in inclement weather * Are you tired, upset, fatigued, ill? Are you taking prescription or over-the-counter medication? Are you emotionally upset? NOTE: No one is allowed so that drive a USC vehicle while under the influence of alcohol! * * Pedestrians have the right of way Avoid sidewalks when possible Drive slow Avoid driving during class change times , if possible. Avoid driving on the grass unless necessary * Do not dismount vehicle before it has come so that a complete stop Engage the brake Turn off the engine Take the key * If you are driving at night does the cart have: working headlights? brake lights? turn-signal lights Drive cautious ? pedestrians may not see you coming. Check the lights before driving at night. * Always tie-down your load Always set your brake once you get so that your destination After loading, check so that see if all four wheels still touching the ground? * Do not exceed load capacity Balance the load Secure the load Be sure you can see behind the vehicle Loads can change on steep grades No one rides in the back * * Know the vehicle you are driving. Be aware of your surroundings. Do not ?horse around? alongside the vehicle Drive slow. * You may now finish this safety training tutorial by completing the OSHA Assessment Quiz.

To Write this Article, I had done research in Universidade Federal do Esp??rito Santo BR.

Course overview Introduction Objective of the course Sources Workshops

Contents of Article

Course overview Introduction Objective of the course Sources Workshops in addition to Homework Midterm exams Final Exam Equation sheets Labs Grading PHY 22 too easy? You still have a chance so that switch so that PHY 42 How so that study in consideration of physics class How so that do physics problems PHY 2 PHY 22 Phases of matter Inside atoms Inside nucleus Nature?s scales My research LHC H…gg H…ZZ*…4l Electricity Inside atoms Electric charge Insulators in addition to conductors Induced charge Electroscope Test problem # Coulomb?s law System of charges This week My research getting inside atoms

Course overview Introduction Objective of the course Sources Workshops www.phwiki.com

* Lecture I * Physics 122, Fall 2012 Course overview * Lecture I * Introduction Instructor Prof. Regina Demina Office B&L 367 Phone 275-7357 Email profdemina@gmail Office hour Mon 3-4 pm * Lecture I * Novosibirsk * Lecture I * Objective of the course thorough understanding of the basic physics concepts ability so that use them in applications * Lecture I * Sources Text book Physics in consideration of Scientists in addition to Engineers, Volume II Forth Edition by Douglas C. Giancoli Class web site /pas.rochester.edu/~regina/PHY122 Lecture notes; Homework assignments Workshop modules Equation sheets in consideration of tests, test solutions Important dates in addition to links * Lecture I * Workshops in addition to Homework Solving problems systematically is important. Peer-lead study groups ? workshops Participation in workshops will count 5% of your final grade. Workshops start next week Participation in workshops = 5% of your final grade, need so that participate (not just attend!) in at least 10 workshops so that get full grade. Homework problems are similar but not identical so that workshop modules Homework problems = 5% of your final grade. Questions on workshop scheduling: “Dev Ashish Khaitan” * Lecture I * Midterm exams There will be two midterm exams during the semester. Both will count. There will be no makeup exam. You can bring a calculator, a pencil in addition to a ruler. 40% of your grade. * Lecture I * Final Exam December 17, 7:15 pm Final exam is based on the entire course PHY122. Last homework will be based on the entire course so that give you more time so that prepare in consideration of the final. 40% of the final grade * Lecture I * Equation sheets No notes or equation sheets may be brought so that exams. However, a sheet of useful equations will be provided during the test. You can view these sheets in advance, will be linked from course schedule on the web. Please note that past experience has shown that having equations available does not guarantee success — understanding is the key. * Lecture I * Labs The laboratory is a required in addition to integrated part of the course. A passing grade in laboratory is required so that pass the course: 10% of the grade Questions should go so that physlabs@pas.rochester.edu NB. I am not allowed so that reveal this person?s identity. * Lecture I * Grading Workshops: 5% Homework: 5% Hour Exams: 40% Final Exam: 40% Laboratory: 10% Total: 100% 90% or above: A 88-89.9 ? A- 85-87.9 ? B+ 80% – 85% : B 78-79.9 ? B- 75-77.9 ? C+ 70% – 75%: C 68-69.9 ? C- 65-67.9 ? D+ 60% – 65%: D Under 60% : E * Lecture I * PHY122 too easy? You still have a chance so that switch so that PHY142 * Lecture I * How so that study in consideration of physics class Look through lecture notes first In lectures I?ll give you all the information that you need so that survive in this class Read the suggested sections from the text book Read the summary first ? concentrate on what?s important Don?t overdo the reading part, try so that understand not memorize Pay attention so that Figures, spend more time on them than on text Examples, try so that work out the problem yourself first Equations (try so that analyze, e.g. if the charge doubles the Coulomb force on it will double as well) * Lecture I * How so that do physics problems Use the ?How so that do physics problems? guide posted on the course web site While doing first several homework assignments in addition to workshop modules stick so that it religiously This practice will help you during the tests PHY122 is a lot more abstract than PHY121 ? well developed procedures will help you so that get started * Lecture I * PHY 121 Kinematics ? how do objects move? Trajectory, displacement, velocity, acceleration, time Dynamics ? why do objects move? Mass, forceŠ work Conserved quantities Energy ? potential in addition to kinetic Momentum First step into micro world ? kinetic theory Mechanical laws work on molecules Heat is a form of energy * Lecture I * PHY 122 What is the origin of forces? So far we considered only one true force ? gravity Next step ? electricity in addition to magnetism Static ? new conserving quantity ? electric charge Dynamic ? DC in addition to AC Magnetic field Electromagnetic waves ? light * Lecture I * Phases of matter Solid, liquid, gas Matter is built of atoms * Lecture I * Inside atoms Atoms have structure = nucleus + electrons Nucleus has positive electric charge Electron has negative electric charge Nucleus has structure = protons in addition to neutrons Electron so far is believed so that be elementary = unbreakable * Lecture I * Inside nucleus Protons in addition to neutrons consist of quarks, called up in addition to down quarks Quarks are believed so that be elementary * Lecture I * Nature?s scales * Lecture I * My research – LHC Alps Large Hadron Collider located in Europe (France in addition to Switzerland) Circumference 27 km; 7TeV(2010-2011)…8TeV (now)…14 Tev(2014) LHC has uncovered the mechanism behind mass – 2012 Discovery of particle known as Higgs boson Prof Hagen (Rochester) ? one of the six people who predicted this mechanism H…gg * Lecture XII * H…ZZ*…4l * Lecture XII * * Lecture I * Electricity There are two kinds of electric charges ? positive in addition to negative. Like charges (++, or –) repel, unlike charges (+-) attract. * Lecture I * Inside atoms Atoms have structure = nucleus + electrons Nucleus has positive electric charge Electron has negative electric charge (Q= -e) Nucleus = protons (Q=+e) in addition to neutrons (Q=0) Electrons are much lighter in addition to thus more mobile than protons or neutrons. * Lecture I * Electric charge The net charge is conserved. Electric charge is measured in Coulombs. Electron has negative charge (e=-1.60.10-19 C), nucleus ? positive. Atom is electrically neutral. Nucleus is heavy, electron is light. Usually charge is transported by electrons. By acquiring more electrons bodies become negatively charged (Q= -Ne .e) By loosing electrons bodies become positively charged (Q= +Ne .e). * Lecture I * Insulators in addition to conductors In solids atoms in addition to their nuclei are ?locked? in their position in addition to hard so that move. Insulators have complete or almost complete electron shells ? these electrons are tough so that move around. Conductors (usually metals) have one or two electrons on the outer shell ? ?free? electrons. * Lecture I * Induced charge Bodies can be charged by Conduction (direct contact) Induction ? create charge separation Break into pieces ?Ground? one end ? charge leaks into the Earth. Always think, where electrons went ? they are the ones so that move. * Lecture I * Electroscope Electroscope ? a simple device so that detect electric charge. * Lecture I * Test problem #1 Two electrically neutral materials are rubbed together. One acquires a net positive charge. The other must A have lost electrons. B have gained electrons. C have lost protons. D have gained protons. * Lecture I * Coulomb?s law F ? force between two charges(N) Q ? electric charge (C= Coulomb) r ? distance between the two charges (m) k ? constant * Lecture I * System of charges Calculate the net electrostatic force on particle 3. Input: Q1= – 86mC= – 86.10-6 C Q2= + 50mC= + 50.10-6 C Q3= + 65mC= + 65.10-6 C r13=60cm=0.60m r23=30cm=0.30m * Lecture I * This week Sign up in consideration of workshops if you have not done so. Workshops start next week. * Lecture I * My research ? getting inside atoms Fermilab 40 miles west of Chicago Tevatron ? at the moment world?s 2nd highest energy collider 2 teraelectronvolts 6.28 km circumference Top quark discovery – 1996

To Write this Article, I had done research in Universidade Federal do Maranh?œo BR.