Q: Two solid spheres A and B each of radius R are made of materials of densities ρ_{A} and ρ_{B} respectively. Their moments of inertia about a diameter are I_{A} and I_{B} respectively. The value of I_{A} / I_{B} is

Sol: $\large \frac{I_A}{I_B} = \frac{\frac{4}{3}\pi R^3 \rho_A}{\frac{4}{3}\pi R^3 \rho_B}$

$\large \frac{I_A}{I_B} = \frac{\rho_A}{\rho_B} $