A boy of mass 4 kg is standing on a piece of wood having mass 5 kg. If the coefficient of friction between the wood and the floor is 0.5, the maximum force that 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 g = 10 ms?²]
Assuming the rope in the boy's hand is vertical and using a Free Body Diagram (FBD): f? = T R + T = 90 ⇒ R = 90 - T For the piece of wood not to move, f? ≤ µR: T ≤ 0.5 (90 - T) ⇒ T ≤ 30N
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