A body of mass 40kg resting on a rough horizontal surface is subjected to a force `P` which is just enough to start the motion of the body. If `mu_(s)=0.5mu_(k)=0.4 , g=10ms^(-2)` an dthe force `P` is continuously applied on the body, then the accceleration of the body is.

Options

A. zero
B. `1ms^(-2)`
C. `2ms^(-2)`
D. `2.4ms^(-2)`

Answer

B

Explanation

`p=f_(ms)=mu_(3)mg`
When the body starts moving with acceleration a, then `P-f_(ms)=ma`
`mu_(s)mg-mu_(k)mg=ma`
or `a=(mu_(s)-mu_(k))g` or `a=(0.5-0.4)10`
`=0.1xx10ms^(-2)=1ms^(-2)` .