Question

a sphere of radius R=40 and mass M=7.2kg. calculate the moment of inertia about the axis of rotation at a distance of R from the centre of sphere.

Answer 1

$I=\frac 23 mr^2+mr^2=\frac 53 mr^2,$

$I=\frac 53\cdot 7.2\cdot 0.4^2=1.92~kg\cdot m^2.$