A block of mass `M` is tied to one end of a massless rope the other end of the rope is in the hands of a man of mass `2M` as shown in the figure. The block and the man are resting on a rough plank of mass `M` as shown in the figure. The whole system is resting on a smooth horizontal surface. The man pulls the rope. Pulley is massless and frictionless. What is the displacement of the plank when the block meets the pulley ( Man does not leave his position on plank during the pull)

Options

A. `0.5 m`
B. `1m`
C. Zero
D. `2//3 m`

Answer

A

Explanation

`Deltabar(x) = (3M.x + M(x + 2))/(4M) = 0 rArr x = (1)/(2)`