A 48 kg skier skis directly down a frictionless slope angled at 13° to the horizontal. Assume the skier moves in the negative direction of an x axis along the slope. A wind force with component Fx acts on the skier. (Indicate the direction with the sign of your answer.)
(a) What is Fx if the magnitude of the skier's velocity is constant?
(b) What is Fx if the magnitude of the skier's velocity is increasing at a rate of 2.0 m/s2?
(c) What is Fx if the magnitude of the skier's velocity is increasing at a rate of 4.0 m/s2?