The drawing shows an extreme skier at three locations on a ski run a) a straight section,b)a circular section and c)an airborn 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 of the net force at a,b,c?assume there is no friction or air resistance at any point along the ski run.
Choice 1.)2,1,1. 1
Choice2.)4,3,2. 4 I
Choice.3)3,1,3. I. 2.(connectline from 4 to 2)
Choice4.)2,3,2. I
Choice5.)2,1,3. 3
No friction?
straight section. Net force is zero (gravity is negated by upward supporting force)
curved section. Net force is down on the both sides: on the incoming side, speed is increasing down the ramp, and on the up side, speed is decreasing.
in the air: net force is downward, the skier is accelerating downward.
Based on the given information that there is no friction or air resistance, the direction of the net force at each location can be determined as follows:
a) Straight section:
Since the skier is not turning or changing direction on the straight section, the net force should be in the same direction as the skier's motion. Therefore, the direction of the net force at location a is 2.
b) Circular section:
In a circular motion, there is always a centripetal force acting towards the center of the circle. In this case, since there is no friction or air resistance, the only force acting towards the center of the circular section is the net force. Hence, the direction of the net force at location b is 1.
c) Airborne phase:
During the airborne phase in free fall, the only force acting on the skier is the force due to gravity. In this case, the net force should be in the downward direction in line with gravity. Therefore, the direction of the net force at location c is 3.
Therefore, the correct answer is Choice 5: 2, 1, 3.
To determine the direction of the net force at each location on the ski run, we need to understand the concepts of forces acting on the skier in each situation.
a) Straight Section:
In a straight section, the skier is not experiencing any change in direction. This means there is no acceleration in the vertical direction. Therefore, the net force acting on the skier must be zero in the vertical direction. So, the correct choice would be 2 - indicating that the net force is acting horizontally (perpendicular to the vertical direction) at the straight section.
b) Circular Section:
In a circular section, the skier is constantly changing direction towards the center of the circular path. This indicates that there is an acceleration towards the center. According to Newton's second law, the acceleration is directly proportional to the net force acting on an object. Since the skier is moving in a circular path, the net force must point towards the center of the circle. So, the correct choice would be 3 - indicating that the net force is acting towards the center of the circular section.
c) Airborne Phase (Free Fall):
During the airborne phase, the skier is in free fall and only subject to the force of gravity. In free fall, the net force acting on the skier is the gravitational force (mg) acting vertically downward. So, the correct choice would be 2 - indicating that the net force is acting vertically downward during the airborne phase.
Based on the explanations above, the correct choice for the directions of the net force at a, b, and c would be:
Choice 2 - 2, 3, 2.