Q. A ring of radius $r$ and mass $m$ rotates about an axis passing through its centre and perpendicular to its plane with angular velocity $\omega$. Its kinetic energy is
A) $mr\omega^{2}$
B) $mr\omega^{2}/2$
C) $mr^{2}\omega^{2}$
D) $\frac{mr^{2}\omega^{2}}{2}$
Explanation
(d) $K_{R} = \frac{1}{2}I\omega^{2} = \frac{1}{2}mr^{2}\omega^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.