A 63-kg skier coasts up a snow-covered hill that makes an angle of 25 with the horizontal.

Question:

A 63-kg skier coasts up a snow-covered hill that makes an angle of 25° with the horizontal. The initial speed of the skier is 6.6 m/s. After coasting 1.9 m up the slope, the skier has a speed of 4.4 m/s.
(a) Find the work done by the kinetic frictional force that acts on the skis.
(b) What is the magnitude of the kinetic frictional force?