A boy of mass 4kg is standing on a piece of wood having mass 5kg ....

A boy of mass $4kg$ is standing on a piece of wood having mass $5kg$. If the coefficient of friction between the wood and the floor is $0 . 5,$ the maximum force that the boy can exert on the rope so that the piece of wood does not move from its place is _______ $N$. (Round off to the Nearest Integer)

[Take \leftg = 10{ms}^{- 2}]$