A 30-kg child sits at the top of a 3-meter slide. After sliding down, the child is traveling 4 m/s. How much PE does he start with? How much KE does he end with? How much energy is lost to friction?

Question

A 30-kg child sits at the top of a 3-meter slide. After sliding down, the child is traveling 4 m/s.  How much PE does he start with? How much KE does he end with? How much energy is lost to friction?

alyssakin · Answer

Thanks again!

agent0smith · Answer

Oh wait there is friction too.

PE = mgh

KE =1/2 mv^2

The energy lost due to friction, will be the difference of those.

agent0smith · Answer

Without friction, the change in PE would equal the change in KE.

greatlife44 · Answer

$$PE_{I}+KE_{I}=PE_{f}+KE_{f}+Wf$$