Question

The moment of inertia of a ring about its geometrical axis is $I$, then its moment of inertia about its diameter will be :

• A. $2I$
• B. $\frac{I}{2}$
• C. $I$
• D. $\frac{I}{4}$

Answer 1

The correct option is B $\frac{I}{2}$

The moment of inertia of the ring about its geometrical axis is I. Using perpendicular axis theorem we have the other two moment of inertia equal and about a diametrical axis. Let it be $I_d$ Thus we have $I_d+I_d=I$ or $I_d=\frac{I}{2}$