Q. Four similar point masses ($m$ each) are symmetrically placed on the circumference of a disc of mass $M$ and radius $R$. Moment of inertia of the system about an axis passing through centre $O$ and perpendicular to the plane of the disc will be
A) $MR^{2} + 4mR^{2}$
B) $MR^{2} + \frac{8}{5}mR^{2}$
C) $mR^{2} + 4MR^{2}$
D) $\frac{MR^{2}}{2} + 4mR^{2}$
Explanation
(d) Total moment of inertia of the system $= \frac{1}{2}MR^{2} + 4mR^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.