Q. The radius of a rotating disc is suddenly reduced to half without any change in its mass. Then its angular velocity will be
A) Four times
B) Double
C) Half
D) Unchanged
Explanation
(a) $L = \frac{1}{2}MR^{2}\omega =$ constant $\therefore\omega \propto \frac{1}{R^{2}}$ [If $m =$ constant]
If radius is reduced to half then angular velocity will be four times
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.