Question

Three spheres, each of mass M and radius R, are arranged as shown in the figure. Then the moment of inertia of the system about $Y{Y}^1$

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

Moment of inertia of Sphere A = $\frac{2}{5}M{R}^2$

Moment of inertia of Sphere B = $\frac{2}{5}M{R}^2+M{R}^2=\frac{7}{5}M{R}^2$

Moment of inertia of Sphere C = $\frac{7}{5}M{R}^2$

Moment of inertia of Sphere D = $\frac{2}{5}M{R}^2+\frac{7}{5}M{R}^2+\frac{7}{5}M{R}^2$

$=\frac{2}{5}M{R}^2+\frac{2M{R}^2}{5}\left(7\right)$

$=\frac{16}{5}M{R}^2$