Question

Find the radius of gyration of a hollow uniform sphere of radius R about its tangent.

• A. $\sqrt{\frac{5}{3}}R$
• B. $\sqrt{\frac{2}{3}}R$
• C. $\sqrt{\frac{3}{5}}R$
• D. $\sqrt{\frac{2}{5}}R$

Answer 1

The correct option is A $\sqrt{\frac{5}{3}}R$

Moment of inertia of a hollow sphere about a tangent, $I=\frac{5}{3}M{R}^2$
$M{K}^2=\frac{5}{3}M{R}^2\Rightarrow K=\sqrt{\frac{5}{3}}R$