Consider the situation as shown in the figure. The system is free to move.

The force by the rope on the block is `FM//(M+m)`

Options

A. Only if the rope is uniform
B. in gravity free space
C. only if `Fgt(M+m)g`
D. in all cases

Answer

D

Explanation

`F-(M+m)g=(M+m)a`
`a=(F)/(M+m)-g`

`T-Mg=Ma`
`T=M(g+a)=(MF)/(M+m)`
In gravity free space: `F=(M+m)a`
`T=MarArrT=(MF)/(M+m)`
If `(M+m)gltF,a=g=(F)/(M+m)`
`Mg-T=MarArrT=(MF)/(M+m)`