In the small block m is kept on planck of mass `M` and a force `F` is applied on planck as shown in diagram then which of the following statements is/are correct
.

Options

A. the acceleration of w.r.t ground is `(F)/(m)`.
B. the acceleration of w.r.t ground is zero
C. the time taken by m to separate from `M` is `sqrt((2lm)/(F))`
D. the time taken by m to separate from `M` is `sqrt((2lM)/(F))`

Answer

B, D

Explanation

Since there is no horizontal force on m in ground fram. Therefore acceleration of m in ground frame is zero Acceleration of `M` is `(F)/(M)`.
`:.` Relative acceleration `=(F)/(M)` from `s = ut + (1)/(2) at^(2)`
`:.t=sqrt((2l)/(F//M))` .