Question

The moment of inertia of an annular disc of mass $M$, outer and inner radii $R$ and $r$, about its diameter is

• A. $M(R^{2} + r^{2}) /2$
• B. $MR^{2}$
• C. $Mr^{2}$
• D. $M (R^{2} + r^{2}) / 4$

Answer 1

Answer: (D)

The moment of inertia of an annular disc about its diameter
$=\frac{M\left(R^{2}+r^{2}\right)}{4}$
where, $R$ is the outer radius of disc, $r$ is the inner radius of disc and $M$ is the mass of disc.