Question

Moment of inertia of a uniform circular ring of mass $m$ and radius $R$ about its diameter is

• A. $m{R}^2$
• B. $2m{R}^2$
• C. $\frac{m{R}^2}{2}$
• D. $\frac{m{R}^2}{4}$

Answer 1

The correct option is C $\frac{m{R}^2}{2}$

For a circular ring, moment of inertia about an axis perpendicular to the plane and passing through the centre is

$I_1=m{R}^2$

From perpendicular axes theorem

$I_D=\frac{I_1}{2}=\frac{m{R}^2}{2}$