a pulley system is used to lift a heavy engine of mass 75.0 kg. the rope passes around three pulleys such that it is necessary to pull 3.00 m of rope through the system in order to lift the engine 1.00 m. (a) ignoring friction, find the amount of force that must be applied to the rope to lift the engine. (b) suppose the actual amount of force required is 325 n - find the efficiency of the pulley system. (c) find the amount of work done by friction if the engine is lifted 1.00 m.