Q. If solid sphere and solid cylinder of same radius and density rotate about their own axis, the moment of inertia will be greater for $(L = R)$
A) Solid sphere
B) Solid cylinder
C) Both
D) Equal both
Explanation
(a) $\frac{I_{Sphere}}{I_{Cylinder}} = \frac{\frac{2}{5}M_{1}R^{2}}{\frac{1}{2}M_{2}R^{2}} = \frac{\frac{2}{5}\left( \frac{4}{3}\pi R^{3}\rho \right)R^{2}}{\frac{1}{2}\left( \pi R^{2}L\rho \right)R^{2}} = \frac{16}{15}$
$\therefore I_{Sphere} > I_{Cylinder}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.