Two small balls of equal mass are joined by a light rigid rod. If they are released from rest in the position shown and slide on the smooth track of diameter 0.5 m in the vertical plane. The speed of balls when A reaches B`s position and B is at B` is:(A)4 m/s(B)4.21 m/s(C)2.21 m/s(D)None of the above

Dear student,

The information given is insufficient to solve the problem. We must know the inital position of block A either by knowing the angle that AB forms with horizontal or the height at which it is.

Anyways, we can find the loss in gravitational potential energy of the system(which comes only due to that of A) and equate it to the gain in kinetic energy of the system( both A and B will have same speed).

Approved