# Homework Help: Work of a child going down a slide

1. Oct 1, 2007

### delecticious

1. The problem statement, all variables and given/known data

A 28.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 24.00 m. When she is partway down the slide, at a height h2 of 15.00 m, she is moving at a speed of 8.00 m/s. Calculate the mechanical energy lost due to friction (as heat, etc.).

2. Relevant equations

non conservative work = (final KE + final PE) - (initial KE + initial PE)

3. The attempt at a solution

initial KE cancels since the child starts from rest so it'll be the sum of the final kinetic energy and potential energy minus the initial potential energy. I worked that out and got -1573.6 J but when I go to check the answer it's wrong and I keep reworking and getting the same answer, but for some reason it's wrong. Anyone know what I'm doing wrong?

2. Oct 1, 2007

### Chi Meson

I never liked that "non-conservative work" forumula. It makes it harder to understand than it is.