Chapter 5Work in addition to EnergyConcept Check – WorkIs it possible to do work on an obje

Chapter 5Work in addition to EnergyConcept Check - WorkIs it possible to do work on an obje www.phwiki.com

Chapter 5Work in addition to EnergyConcept Check – WorkIs it possible to do work on an obje

Mansour, Ali, Features Editor has reference to this Academic Journal, PHwiki organized this Journal Chapter 5Work in addition to EnergyConcept Check – WorkIs it possible to do work on an object that remains at rest 1. yes2. noConcept Check – WorkIs it possible to do work on an object that remains at rest 1. yes2. noWork requires that a as long as ce acts over a distance. If an object does not move at all, there is no displacement, in addition to there as long as e no work done on that object.Does that mean that no work is being done

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WorkConcept Check – Play Ball!!In a baseball game, the catcher stops a 90-mph pitch. What can you say about the work done by the catcher on the ball 1. catcher has done positive work2. catcher has done negative work catcher has done zero workConcept Check – Play Ball!!In a baseball game, the catcher stops a 90-mph pitch. What can you say about the work done by the catcher on the ball 1. catcher has done positive work2. catcher has done negative work catcher has done zero workThe as long as ce exerted by the catcher is opposite in direction to the displacement of the ball, so the work is negative. Or using the definition of work (W = F d cos q ), since = 180o, then W < 0. Note that because the work done on the ball is negative, its speed decreases. Concept Check – Work in addition to TensionA ball tied to a string is being whirled around in a circle. What can you say about the work done by tension1. tension does no work at all 2. tension does negative work3. tension does positive workConcept Check – Work in addition to TensionA ball tied to a string is being whirled around in a circle. What can you say about the work done by tension1. tension does no work at all 2. tension does negative work3. tension does positive workNo work is done because the as long as ce acts in a perpendicular direction to the displacement. Or using the definition of work (W = F d cos q ), since = 90°, then W = 0.Follow-up: Is there a as long as ce in the direction of the velocityConcept Check – Work in addition to FrictionA box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction1. friction does no work at all 2. friction does negative work3. friction does positive work Concept Check – Work in addition to FrictionA box is being pulled across a rough floor at a constant speed. What can you say about the work done by friction1. friction does no work at all 2. friction does negative work3. friction does positive workFriction acts in the opposite direction to the displacement, so the work is negative. Or using the definition of work (W = F d cos q ), since = 180o, then W < 0.Definition of WorkIn order as long as mechanical work to be done: Force must act on object Object must moveWork is a scalar, but it can be + or – (+) if Force in addition to motion are in same direction (–) if Force in addition to motion are in opposite directionsMany as long as ces can do work on the same object. Even friction can do work. Sometimes it appears that no work is being done when it really is, like when you do isometric exercises.Definition of Work Fg = 1.50 x 103 NFa = 345 Nd = 24.0 mmk = 0.220Wa = Wk = Wn= Wg = SW = Which ends up in the as long as m of KESampleFg = 5.00 x 109 NFt = 5.00 x 103 Nd = 3.00 km = 3.00 x 103 mWt = Problem – 1Fa = 35 N = 25°d = 50.0 m Wa = Problem – 3 Problem – 4FgFadqWa = Wk = Wn = Wg = mk = Concept Check – Force in addition to WorkA box is being pulled up a rough incline by a rope connected to a pulley. How many as long as ces are on the box1. one as long as ce2. two as long as ces3. three as long as ces4. four as long as ces5. five as long as cesConcept Check – Force in addition to WorkA box is being pulled up a rough incline by a rope connected to a pulley. How many as long as ces are on the box1. one as long as ce2. two as long as ces3. three as long as ces4. four as long as ces5. five as long as ces Concept Check – Force in addition to WorkA box is being pulled up a rough incline by a rope connected to a pulley. How many as long as ces are doing work on the box1. one as long as ce2. two as long as ces3. three as long as ces4. four as long as ces5. no as long as ces are doing workConcept Check – Force in addition to WorkA box is being pulled up a rough incline by a rope connected to a pulley. How many as long as ces are doing work on the box1. one as long as ce2. two as long as ces3. three as long as ces4. four as long as ces5. no as long as ces are doing workAny as long as ce not perpendicular to the motion will do work:Fn does no workFT does positive workFk does negative workFg does negative workMechanical EnergyWork is the transfer of Mechanical Energy from one as long as m to another.Mechanical EnergyPotential Energy(energy of position)Kinetic Energy(energy of motion)GravitationalElastic Kinetic EnergyKinetic energy is energy of motion. It depends on mass in addition to speed. Kinetic Energy (Units)These are the same units as as long as Work! Coincidence I think not.Concept Check – Kinetic EnergyBy what factor does the kinetic energy of a car change when its speed is tripled 1. no change at all 2. factor of 33. factor of 64. factor of 95. factor of 12 Mansour, Ali 4-Wheel & Off-Road Features Editor www.phwiki.com

Concept Check – Kinetic EnergyBy what factor does the kinetic energy of a car change when its speed is tripled 1. no change at all 2. factor of 33. factor of 64. factor of 95. factor of 12Since the kinetic energy is 1/2 mv2, if the speed increases by a factor of 3, then the KE will increase by a factor of 9.Concept Check – Kinetic EnergyIs it possible as long as the kinetic energy of an object to be negative1. Yes2. NoConcept Check – Kinetic EnergyIs it possible as long as the kinetic energy of an object to be negative1. Yes2. NoThe kinetic energy is 1/2 mv2. The mass in addition to the velocity squared will always be positive, so KE must always be positive.

Gravitational Potential EnergyPEg = mghgravitational PE = mass free-fall acceleration heightConcept Check – Gravitational Potential EnergyIs it possible as long as the gravitational potential energy of an object to be negative1. Yes2. NoConcept Check – Gravitational Potential EnergyIs it possible as long as the gravitational potential energy of an object to be negative1. Yes2. NoGravitational PE is mgh, where height h is measured relative to some arbitrary reference level where PE = 0. For example, a book on a table has positive PE if the zero reference level is chosen to be the floor. However, if the ceiling is the zero level, then the book has negative PE on the table. It is only differences (or changes) in PE that have any physical meaning.

Wheel in addition to AxleThe efficiency of a squeaky pulley system is — %. The pulleys are used to raise a mass to a certain height. What as long as ce is exerted on the machine if a rope is pulled — m in order to raise a — kg mass a height of — meff dindoutSamplemgFin =

Mansour, Ali Features Editor

Mansour, Ali is from United States and they belong to 4-Wheel & Off-Road and they are from  Los Angeles, United States got related to this Particular Journal. and Mansour, Ali deal with the subjects like Off-Road Vehicles; Trucks and Sport Utility Vehicles

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