Question

a uniform sphere has a radius of 0.10 m. the moment of inertia of the sphere when axis

of rotation is located at its center is 0.08 kg-m2

, find the mass of the sphere.

Answer 1

$$J=\frac{2}{5}mR^2$$

$$m=\frac{5J}{2R^2}=\frac{5*0.08}{2*0.10^2}=20\:\rm kg$$