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Physics Final Exam ReviewChapter 10: Work, Energy, and Simple Machines●Work:the process of changing the energy in a system○Scalar Quantity○Force and displacement must be parallel-No work→no motion, perpendicular force and displacement○Unit: Joule (J)○1 Joule=1 Nm●Power: the amount of energy transferred in a unit of time (rate at whichwork is done)○Unit: Watt (W)●Positive work increases the energy in a system; negative work decreases it●Two people apply the same force for the same distance in differentamounts of time. Their work will be the same and their powerwill bedifferentChapter 11: Energy and its Conservation●Forms of Energy○Kinetic Energy: an object’s energy due to motion○Potential Energy: the energy stored in an object due to its state,position, or form→W=ΔPE-Examples: compressing spring, stretched rubber band, drawnbow and arrow
○Gravitational Potential Energy: potential energy of an object due toits position above the reference level-Reference Level: location at which PE is chosen to be zero■Height is positive above it and negative below it○Mechanical Energy: the sum of the kinetic and potential energy in asystem●Work-Energy Theorem: work done on an object is equal to the change inkinetic energy→W = ΔKE○Negative work=decreasing KE○Positive work=increasing KE-If an object starts from rest, W=KEf-If an object comes to rest, W=-KEi●Law of Conservation of Energy: in a closed, isolated system the total energyremains the same○Closed: nothing enters or leaves○Isolated: no external forces○KEi+PEi=KEf+PEfChapter 12: Momentum and its Conservation●Momentum: product of an object’s mass and velocity●Impulse: the product of the average force on an object and the time intervalover which it acts; vector●Impulse-Momentum Theorem: the impulse of an object is equal to thechange in momentum→I=ΔP●