1. The problem statement, all variables and given/known data A truck is traveling at 11.1 m/s down a hill when the brakes on all four wheels lock. The hill makes an angle of 15.0° with respect to the horizontal. The coefficient of kinetic friction between the tires and the road is 0.750. How far does the truck travel before coming to a stop? Use energy to solve this problem. 2. Relevant equations fk = Ef - Ei fk = μk*FN FN=mgcos15° 3. The attempt at a solution First, I found the work done by the friction force: Wfk = S(μkFN)cos180° Wfk = μk(mgcos15°)(-1) Then I solved for the work done by friction using the energy equation: W = 1/2(mv2) +mgy - 1/2(mvi2) -mgyi W = 0 + mgy - 1/2(mvi2) - 0 then I set the two equations equal to one another: μk(mgcos15°)(-1) = mgy - 1/2(mvi2) the m's cancelled out and I solved for y: y = μk(gcos15°)(-1) + 1/2(vi2) / g and plugged in values: y = (0.750)(9.8m/s2)(cos15°)(-1) + 1/2(11.0)2 / 9.8m/s2 and got: y = 6.90 m knowing that the truck was traveling at 15°, sin15° = y/s s = 6.90/sin15° s = 26.7m the correct answer should be 13.5m. Any help/advice would be much appreciated.