If a boy's mass is 53kg, what force must be exerted as he climbs the ladder?If the length of the ladder is 4.8m he climbs the ladder 0.4min, how much work does the boy do, and what is his power output?What simple machine principle does the ladder work on? Ir the height of the wall is 3.5m, Determine the mechanical advantage of the ladder.what is the mass of the girl?