Question

If mass M and radius of solid sphere is R, then moment of Inertia about
diameter is :
(A) 2/3MR^2
(B) 2/5MR^2
(c) 3/5MR^2
(d) 7/5MR^2​

Answer 1

A solid sphere of mass M and radius R having moment of inertia I about its diameter is recast into a solid disc abut an axis passing the edge and perpendicular to the plane remains l. Then R and r are related as. From(i) and (ii), 25MR2=32Mr2⇒r=2√15R.