A 25 kg child slides down a playground slide at a constant speed. The slide has a height of 3.0 m and is 7.0 m long. Using energy considerations, find the magnitude of the kinetic friction force acting on the child.

Answer 1

Since the kinetic energy does not change,

Friction work = (Friction force)*(sliding distance) = Potential energy loss

M g*3.0 m = Ff*7.0 m

Ff = (3/7) M g = 105 J
is the friction force that resists motion.

Answer 2

thank you, will teach the class this tomorrow (I didnt know how to do it myself)