Question

Sam, whose mass is 75 kg, straps on his skis and starts down a 63 m -high, 20° frictionless slope. A strong headwind exerts a horizontal force of 200 N on him as he skies. (Horizontal relative to level ground, not aligned with the slope.) What is his speed at the bottom?

Answer 1

KE = PE.
0.5M*V^2 = M*g*h,
Divide both sides by M:
0.5V^2 = g*h,
0.5V^2 = 9.8 * 63,
V = 35 m/s.

Answer 2

remember to deduct the work done by the wind

63 m * 200 N * cos(20º)