Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

Published by Pearson
ISBN 10: 0321740904
ISBN 13: 978-0-32174-090-8

Chapter 12 - Rotation of a Rigid Body - Conceptual Questions - Page 347: 12

Answer

See the detailed answer below.

Work Step by Step

When the diver needs to increase his angular speed, he needs to decrease his body moment of inertia so he can make 3 rotations at the same time interval rather than one and a half rotations. We can use the conservation of angular momentum here. $$I_1\omega_1=I_2\omega_2$$ where $I_1$ refers to the pike position and $I_2$ refers to the tuck position. $$\dfrac{\omega_2}{\omega_1}=\dfrac{I_1}{I_2}$$ When we need $\omega_2\gt \omega_1$, then $I_1/I_2$ must be greater than 1. This means that $I_1\gt I_2$. So he has to decrease his moment of inertia by using the tuck position so he can rotate faster.
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.