Ignoring friction within the lift mechanism, the work is:
Work = Force x Distance
The force is gravity = mg, the skier's mass, m = 76.9 kg, times the acceleration due to gravity, g = 9.8 m/s/s.
Work = mg x Distance = (76.9)(9.8) x Distance = 70.36 x distance
The distance is the distance moved against the force, so it is just the vertical distance up that the skier moves, not her horizontal distance. Her vertical distance is:
Distance = (1377.1 m)·sin(25.2°)
So the work done is:
Work = (70.36) x (1377.1 m)·sin(25.2°)
Use your calculator to compute the answer.
