A painter of mass M stands on a platform of mass m and pulls himself up by two ropes which hang over pulley as shown in fig. He pulls each rope with force F and moves upward with a uniform acceleration a. find a, neglecting the fact that no one could do this for long time.

Options

A. `(4F+(2M+m)g)/(M+2m)`
B. `(4F+(M+m)g)/(M+2m)`
C. `(4F-(M+m)g)/(M+m)`
D. `(4F-(M+m)g)/(2M+m)`

Answer

C

Explanation

From fig.,
`2F+N-Mg=Ma`
`2F-mg-N=ma`
`4F-(M+m)g=(M+m)a`
`a=(4F-(M+m)g)/(M+m)`.