Question

A solid sphere of radius R has moment of inertia I about its geometrical axis. If it is melted into a disc of radius r and thickness t. If its moment of inertia about the tangential axis (which is perpendicular to plane of the disc), is also equal to I , then the value of r is equal to a) (2/√15)R. b)(2/√5)R c) (3√15)R d)(√3/√15)R

Answer 1