Essential University Physics: Volume 1 (3rd Edition)

Published by Pearson
ISBN 10: 0321993721
ISBN 13: 978-0-32199-372-4

Chapter 5 - Exercises and Problems - Page 87: 45



Work Step by Step

We need to know the two forces causing the child to go downward. We know that there is the force of gravity pulling the child down the hill: this equals $mgsin\theta$. However, there is also a frictional force acting directly up the hill: this is given by $=F_n\mu$. The normal force is equal to the cosine of theta times the force of gravity, so we find: $F_f=\mu mgcos\theta$. The child is going at a constant speed, so we know that the two forces are equal. Thus: $\mu mgcos\theta=mgsin\theta\\ \mu=\frac{sin8.5}{cos8.5}=.149$
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.