Physics
posted by Tina .
After delivering his toys in the usual manner, Santa decides to have some fun and slide down an icy roof. The roof is 7 m in length and makes an angle of 41° with the horizontal. He starts from rest at the top of the roof and accelerates at the rate of 3.9 m/s2. The edge of the roof is 6.0 m above a soft snowbank upon which Santa lands. What is the coefficient of friction between Santa and the roof?

You are being given more information than needed to answer the question. The roof length and roof edge height do not matter.
The net accelerating force is
M*a = 3.9 m/s^2 *M
= Mgsin41  Mgcos41*U
Santa's mass M cancels out. Solve for the friction coefficient U.
3.9 = 6.43  7.40 U
7.40 U = 2.53
U = 0.34