With what minimum velocity u should block be projected from left end A towards end B such that it reaches the other end B of conveyer belt moving with constant velocity v? Friction coefficient between block and belt is ?.
(A) ?(?gL)
(B) ?(2?gL)
(C) ?(3?gL)
(D) 2?(?gL)
Ans. (B) ?(2?gL)