Physics Homework Help?

 A 22-kg child starts from rest and slides down a slide that is 2.5 m high. At the bottom of the slide, the child is moving 1.91 m/s. 

How much work, in joules, was done by the nonconservative force of friction on the child? 

Ash2021-04-02T20:10:48Z

Initial Potential energy = Kinetic energy at the bottom + Work due to friction
Work due to friction = PE - KE
W(fr) = mgh - ½mv²
W(fr) = m(gh -½ v²)
W(fr) = (22 kg)[(9.81 m/s²)(2.5 m) - ½ (1.91 m/s)²]
W(fr) = 499 J