Question

Two equal masses m each are placed at a distance d apart. The velocity imparted to one of the masses perpendicular to the line joining the two masses so that their relative separation is unchanged is

(A)  √(2Gm/d)

(B)  √(Gm/d)

(C)  2√(Gm/d)

(D)  √(Gm/2d)

Answer 1

Correct option (A)  √(2Gm/d)

Explanation: 

Let velocity be v, centre of mass moves with a velocity v/2

from centre of mass frame