Question

A uniform disc of mass 'm' and radius R is placed on a smooth horizontal floor such that the plane surface of the disc is in contact with the floor. A man of mass m/2 stands on the disc at its periphery. The man starts walking along the periphery of the disc. The size of the man is negligible as compared to the size of the disc. Then the centre of disc.
(A) moves along a circle of radius R3 (B) moves along a circle of radius 2R3
(C) moves along a circle of radius R2 (D) does not move along a circle

Answer 1

Dear Student ,
The sum of centre of mass disc and man shall always remain at rest .Since the man always at the periphery of the disc the centre of disc shall always be at distance R/3 from centre of mass of two body system .
Therefore , hence the centre of disc moves on the circle of radius R/3 .
So the correct option is A .
Hope it helps you .