Question

Two rotating bodies have same angular momentum but their moment of inertia are $I_1$ and $I_2$ respectively ($I_1>I_2$). Which body will have higher kinetic energy of rotation.

• A. first.
• B. second.
• C. both will have same kinetic energy.
• D. not possible to predict.

Answer 1

Answer: (B)

second.

$K=\frac{L^2}{2I}$
Given, $L_1=L_2$
$\frac{K_1}{K_2}=\frac{\frac{L_1^2}{2I_1}}{\frac{L_2^2}{2I_2}}=\frac{I_2^2}{I_1^2}$
Since $I_1>I_2{K}_1<K_2$ ie the second body will have higher kinetic energy of rotation.