Q. Moment of inertia of a disc about its own axis is $I$. Its moment of inertia about a tangential axis in its plane is
A) $\frac{5}{2}\ I$
B) $3\ I$
C) $\frac{3}{2}\ I$
D) $2\ I$
Explanation
(a) $\frac{1}{2}MR^{2} = I \Rightarrow MR^{2} = 2I$
Moment of inertia of disc about a tangent in a plane
$= \frac{5}{4}MR^{2} = \frac{5}{4}(2I) = \frac{5}{2}I$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.