The friction coefficient between the board and the floor shown in figure is `mu` Find the maximum force that the man can exert on the rope so that the board does not slip on the floor

Explanation

`uarr : F + N = (m + m)g - F`
`f_(max) = mu N = mu[(M + m)g - F]`
`rarr : F = f_(max)`
`F = mu[M + m)g - F]`
`F = (mu(M + m)g)/( 1 + mu)`