A uniform disc of mass `'m'` and radius `R` is placed on a smooth horizontal floor such that the plane surface of the disc 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 center of disc.

Options

A. moves along a circle of radius `(R)/(3)`
B. moves along a circle of radius `(2R)/(3)`
C. moves along a circle of radius `(R)/(2)`
D. does not move along a circle

Answer

A

Explanation

The centre of mass of man `+` disc shall always remain at rest. Since the man is always at periphery of disc, the centre of disc shall alwas be at distance `R//3` from centre of mass of two body system .Hence centre of disc moves in circle of radius `R//3`