Question

We have two spheres, one of copper and other of iron, of same mass. Which sphere will have
larger inertia?

Answer 1

Answer:

Well both are spheres and considering their densities , to have same mass , steel sphere must have a smaller volume and hence smaller radius as compared to wooden sphere. This is concluded , assuming both of the spheres are solid. Hence it's clear that moment of inertia of the wooden sphere is more than moment of inertia of the steel sphere as I= mk^2 , k = radius of gyration = constant * radius .