Practice!

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?

meters

Solution

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.