A 50-kg student on a sled starts from rest at a vertical height of 20 m above the horizontal base of a hill and slides down.
a) If the sled and the student have a speed of 10 m/s at the bottom of the hill, this system is (1) conservative, (2) non-conservative, or (3) none of the preceding. Why?
b) What is the work done by the non-conservative force?