A block of mass m is resting on a smooth horizontal surface , One end of a uniform rope of mass `(m/3)` is fixed to the block, which is pulled in the horizontal direction by applying force F at the other end. The tension in the middle of the rope is

Options

A. `8/7 F`
B. `1/7 F`
C. `1/8 F`
D. `7/8 F`

Answer

D

Explanation

Acceleration of the system
`a=F/((m+m/3))`
`therefore` Tension in the middle of the rope
`T=(m+m/6)a`
or `T=(7m)/6. (3F)/(4m)`
or `T=7/8 F`