A solid sphere and a disc of same radii are falling along an inclined plane without slip. One reaches earlier than the other due to.

Options

A. different radius of gyration
B. different size
C. different friction
D. different moment of inertia

Answer

A

Explanation

(a) `a = (g sin theta)/(1 + (I)/(MR^2)) = (g sin theta)/(1 + (K^2)/(R^2)) [because I = MK^2]`
Clearly one reaches earlier that other due to different radius of gyration.