A 0.2-kg stone is attached to a string and swung in a circle of radius 0.6 m on a horizontal and frictionless surface. If the stone makes 150 revolutions per minute, the tension force of the string on the stone is:
A) 0.03 N
B) 0.2 N
C) 0.9 N
D) 1.96 N
E) 30 N

Question

Quizplus · Accepted Answer

The tension force is the centripetal force required to keep the stone moving in a circle. The centripetal force $ F_c $ is given by $ F_c = m \cdot \omega^2 \cdot r $, where $ m = 0.2 \, \text{kg} $, $ r = 0.6 \, \text{m} $, and $ \omega = \frac{2\pi \cdot 150}{60} \, \text{rad/s} $. Calculating this gives $ F_c = 30 \, \text{N} $.

A 02-Kg Stone Is Attached to a String and Swung in in a Circle