Question

Three solid spheres each of mass $P$ and radius $Q$ are arranged as shown in fig. The moment of inertia of the arrangement about $Y{Y}^{\prime }$ axis

• A. $\frac{7}{5}P{Q}^2$
• B. $\frac{14}{5}P{Q}^2$
• C. $\frac{16}{5}P{Q}^2$
• D. $\frac{5}{14}P{Q}^2$

Answer 1

Answer: (C)

$I=\left(\frac{2}{5}m{R}^2\right)+\left(\frac{2}{5}m{R}^2+m{R}^2\right)+\left(\frac{2}{5}m{R}^2+m{R}^2\right)$
$=\frac{16}{5}m{R}^2$