Sample Problem

If the change in kinetic energy of a hockey puck hit across the ice by a hockey stick is 100 joules, and the average force that the stick exerts on the puck is 200 N, what is the distance that the force is exerted over?



Since ∆K = Work, and Work = Fd, we know that a 100J change in kinetic energy is equal to Fd. F = 200, and d is the unknown. If we solve for d, we get d = W/f = 100/200 = .5 meters. The force acts over .5 meters.