A solid sphere A and a hollow sphere B have the same mass and the same outer radius. Their moments of inertia about diameters are Iₐ and Iᵦ respectively. Which relation is correct?
Options

Question

A solid sphere A and a hollow sphere B have the same mass and the same outer radius. Their moments of inertia about diameters are Iₐ and Iᵦ respectively. Which relation is correct?

G1 Physics · Accepted Answer

For equal mass M and radius R: solid sphere Iₐ=2MR²/5, while hollow sphere Iᵦ=2MR²/3. Therefore Iₐ<Iᵦ, so option C.