Final answer:
The skier's speed remains the same when he reaches the top of the frictionless slope but decreases when a frictional force acts on the skis.
Step-by-step explanation:
In this question, we are given that a skier is moving with a speed of 8.33 m/s and starts to slide up an 8.44° frictionless slope. We need to find the skier's speed when he reaches the top plateau and when an 80 N frictional force acts on the skis.
When the skier coasts up the hill, his speed remains the same because the slope is frictionless. So, his speed when he reaches the top plateau is 8.33 m/s.
When an 80 N frictional force acts on the skis, it opposes the motion of the skier. We can calculate the acceleration of the skier using Newton's second law, and then calculate the final speed using the kinematic equation. The skier's speed when he reaches the upper level would depend on the magnitude of the frictional force and would be less than 8.33 m/s.