Question

There is a non-conducting rod of length L and negligible mass with two small balls each of mass m and electric charge Q attached to its ends.the rod can rotate about a fixed vertical axis crossing it distance L/4 from one of its ends. A uniform horizontal electric field E is established. 1.At first the rod is in unstable equilibrium.If it is disturbed slightly in this position, the max velocity attained by the ball which is closer to the axis in subsequent motion is?

Answer 1