Question

the drawing shows an extreme skier at three locations on a ski run: (a) a straight section, (b) a circular section, and (c) an airborne phase in which the skier is in free - fall. at the right of the drawing are four possible directions for the net force that acts on the skier. what is the direction of the net force at a, b, and c? assume that there is no friction or air resistance at any point along the ski run.
o 2,1,3
o 2,1,1
o 2,3,2
o 4,3,2
o 3,1,3

Explanation:

Step1: Analyze point A

On the straight - section (A), the only force acting on the skier is the component of the gravitational force along the slope. The direction of the net - force is down the slope, which corresponds to direction 2.

Step2: Analyze point B

At the circular section (B), the net force provides the centripetal force. The centripetal force always points towards the center of the circle. So the net force on the skier at point B points upwards (towards the center of the circular path), which corresponds to direction 1.

Step3: Analyze point C

In the airborne phase (C), the skier is in free - fall. The only force acting on the skier is the gravitational force, which acts downwards. So the net force on the skier at point C is downwards, which corresponds to direction 3.

Answer:

2, 1, 3