A body of mass `m` is kept on a rough horizontal surface of friction coefficient `m` . A force `P` is applied horizontally , but the body is not moving .Find the net force `F` excerted by the surface on the body .

Explanation

Since the body is not moving
So ` f = P and N = mg`
Net force appling by surface on the body
`F = sqrt(f^(2) + N^(2)) = sqrt(P^(2) + m^(2) g^(2))`