Physics (10th Edition)

Published by Wiley
ISBN 10: 1118486897
ISBN 13: 978-1-11848-689-4

Chapter 5 - Dynamics of Uniform Circular Motion - Check Your Understanding - Page 136: 14


The string is more likely to break when the circle is vertical.

Work Step by Step

When the circle is horizontal, tension $T$ in the string is the only force contributing to the centripetal force $F_c$. The stone's weight $W$ is not related to $F_c$. When the circle is vertical, however, $T$ and $W$ interact to contribute to $F_c$. At the bottom of the circle, $T$ opposes $W$ so $F_c=T-W$ or $T=F_c+W$ As we can see, when the circle is vertical, there are points where $T$ has to both support $F_c$ and counter $W$, meaning its value is greater than tension $T$ when the circle is horizontal. The string is more likely to break as a result.
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.