Q. A particle performs uniform circular motion with an angular momentum $L$, if the frequency of particles motion is doubled and its KE is halved, the angular momentum becomes
A) $4L$
B) $0.5L$
C) $2L$
D) $0.25L$
Explanation
(d) From $E = \frac{1}{2}r\omega^{2}$, we find that when frequency $(n)$ is doubled, $\omega = 2\pi n$ is doubled, $\omega^{2}$ becomes 4 times. As $E$ reduces to half, $I$ must have been reduced to $\frac{1}{8}$ th. From $L = I\omega,\ L$ becomes $\frac{1}{8} \times 2 = \frac{1}{4}$ times $ie,\ 0.25\ L$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.