Question

A painter climbs a ladder leaning against a smooth wall. At a certain height, the ladder is on the verge of slipping. Let the mass of the painter be 85.0 kg, length = 5.80 m, the ladder’s mass to be 37.0 kg, è = 51.0°, and the coefficient of friction between ground and ladder be 0.470. (c) If the ladder is uniform, what is the lever arm for the force of gravity acting on the ladder? (do not include the man)