Question

Two identical concentric rings each of mass $m$ and radius $R$ are placed perpendicularly. What is the moment of inertia about axis of one of the rings

• A. $\frac{3}{2}M{R}^2$
• B. $2M{R}^2$
• C. $3M{R}^2$
• D. $\frac{1}{4}M{R}^2$

Answer 1

Answer: (A)

Since the axis of two rings are also perpendicular to each other, therefore applying the theorem of perpendicular axes
$I=M{R}^2+\frac{1}{2}M{R}^2$
$\frac{3}{2}M{R}^2$