- 89

- 0

**kinetic friction -- toughie!**

Problem:

A skier weighing 90 kg starts from rest down a hill inclined at 17 degrees. He skis 100 m down the hill and then coasts for 70 m along level snow until he stops. FIne the coefficient of kinetic friction between the skis and the snow. What velocity does the skier have at the bottom of the hill?

I can find the position of the skier down the hill as a function of velocity. I can also find the position of the skier along the level ground as a function of velocity (I think I have this part of the problem right). I get x = (v^2)/(g sin 17 - uk cos 17) for the motion on the hill and x = -v^2/(uk g) for the motion on the level snow. But I'm struggling with how to solve for v at the bottom of the hill and uk (coefficient of kinetic friction)! Please help! Your input is GREATLY appreciated :)

According to the answer given in the book, I should get uk=.18 and v at bottom of hill = 15.6 m/s.