Work And Energy 4

Question

A skier of mass 62 kg is pulled up a slope by a motor-driven cable.
(a) How much work is required to pull him 80 m up a 30° slope (assumed frictionless) at a constant speed of 3.3 m/s?

J
(b) What power must a motor have to perform this task?

hp

Answer 1

Since there is no friction, the amount of work required is simply given by the change in potential energy.   The height of the ramp is given by  80m * sin 30 = 40 meters.   So the amount of work done is given by 80m * 62kg *9.8 m/s^{2 =} 24.3kJoules