2. A launch is a mechanical lifting or hauling device consisting of a rope, cable, or chain Musing around a horizontal rotating o'runi, turned by a crank or by motor or other power source. We use one at our cottage to move heavy things like fallen trees a) A motor on an electric winch is only 45% efficient. How much work must be done to winch a 200 kg load of bricks up 4 oors on a construction site if each oor is 4.0 m? b) What power must the motor generate to accomplish this in 42 s