A force `F` equals to `100N` is applied on `30kg` box inside which a `10kg` mass is hanging with the help of a massless string as shown in figure. Coefficient of friction between box and surface is `0.1`. Initially system is at rest, then at this instant acceleration of box will be

Options

A. `4m//s^(2)`
B. `6m//s^(2)`
C. `2m//s^(2)`
D. `1.5m//s^(2)`

Answer

C

Explanation

Ans.(3)
`F_(n et)=F-f=100-40-60N`
`rArra=(F_(n et))/(m)=2m//s^(2)`