[SOLVED] Motion on a Plane 1. The problem statement, all variables and given/known data A professional skier's initial acceleration on fresh snow is 90% of the acceleration expected on a frictionless, inclined plane, the loss being due to friction. Due to air resistance, his acceleration slowly decreases as he picks up speed. The speed record on a mountain in Oregon is 180 kilometers per hour at the bottom of a 25 degree slope that drops 200 m. a) What exit speed could a skier reach in the absence of air resistance? b) What percentage of this ideal speed is lost to air resistance? 2. Relevant equations Vf^2=Vi^2+2at a= (9.8)sin (theta) 3. The attempt at a solution The correct answer for part a is 214 km/hr and the correct answer for part b is 16%. Do I take the 90% of the acceleration after finding acceleration with a= (9.8)sin (theta), I just need to add the 10% back to the acceleration? The 200m drop; is this the opposite of the angle or is this the hypotenuse? I believe it is the hypotenuse, but it if it was the opposite of the angle I should be able to find the adjacent and hypotenuse of the angle with inverse tangent, correct? Please, if you have any tips or pointers for this problem I am grateful to hear them!