Conservation of en Conservation of energy The says energy cannot be gained or lost... just transformed. time PE changes into KE... which turns back into PE. Any difference in is called Work can be used to solve for work. Work Force Distance [m) 5.0 m 5.0 m 2.6- Work Energy in, Energy out Energy is a push or pull over some distance OR the difference between the energy at start minus finish. Conservation of energy equations First, determine what forms of energy you have at the beginning and end Law of Com scenario. Off the ground? LEbefore + W = LEafter Push or pull? Velocity? Next, plug in known values to solve for unknowns. Determining energy in and out A 0.5 kg ball is dropped from the top of a 100 m tall building. Right before hitting the ground, the ball has a velocity of 20 m/ s. Energy in? energy. Object is off the ground. Energy out? energy. Object is moving