This is from the shorter set of passages, where there's only 3 passages, for a total with the discretes.
20. A skier is given a strong push so that he slides up the hill in Figure 2 for a certain distance (uk = 0.1). When he gets to the highest point, he slides back down. How does the acceleration of the skier on this ascent compare to the acceleration of the skier on his descent? (Do not consider the acceleration during the initial push).
A. The acceleration on the descent is smaller in magnitude than on the ascent.
Choice A is the best answer. Friction and gravitational force both act on the skier as he goes up the hill and as he slides back down. However, as he moves up the hill, friction and gravity act in the same direction, so these two forces add together. As he slides down the hill, gravity pulls him downward, while friction pulls upward. Now these two forces subtract. The net force acting on the skier as he moves up the hill is greater than the net force acting on the skier as he moves down the hill, so acceleration on the ascent is greater than on the decent.
What I don't understand is if gravity AND friction are working on the skier during the ascent, then how would his acceleration be faster?
20. A skier is given a strong push so that he slides up the hill in Figure 2 for a certain distance (uk = 0.1). When he gets to the highest point, he slides back down. How does the acceleration of the skier on this ascent compare to the acceleration of the skier on his descent? (Do not consider the acceleration during the initial push).
A. The acceleration on the descent is smaller in magnitude than on the ascent.
Choice A is the best answer. Friction and gravitational force both act on the skier as he goes up the hill and as he slides back down. However, as he moves up the hill, friction and gravity act in the same direction, so these two forces add together. As he slides down the hill, gravity pulls him downward, while friction pulls upward. Now these two forces subtract. The net force acting on the skier as he moves up the hill is greater than the net force acting on the skier as he moves down the hill, so acceleration on the ascent is greater than on the decent.
What I don't understand is if gravity AND friction are working on the skier during the ascent, then how would his acceleration be faster?