A man of mass m moves with a constant speed on a plank of mass 'M' and length 'L' kept initially at rest on a frictionless horizontal surface, from one end to the other in time 't'. The speed of the plank relative to ground while man is moving, is -

A man of mass m moves with a constant speed on a plank of mass 'M' and

1.	A man of mass m moves with a constant speed on a plank of mass 'M' and length 'L' kept initially at rest on a frictionless horizontal surface, from one end to the other in time 't'. The speed of the plank relative to ground while man is moving, is -
Answer» `L/t(M/m)` `L/t(m/(M+m))` `L/t(m/(M-m))` NONE of these Answer :B