1. The problem statement, all variables and given/known data Starting from rest, a 75 kg skier slides down a 17.0 º slope. If the coefficient of kinetic friction between the skis and snow is 0.120 and it takes 28.2 s to get to the bottom, how long is the ski trail? 2. Relevant equations [tex]F = ma[/tex] [tex]s_f = s_i +v_i + 1/2at^2[/tex] 3. The attempt at a solution I drew a diagram and came up with this: The acceleration of the skier down the slope is mgsin(17) the friction going the opposite direction is mgsin(17)0.120. F_net is mgsin(17)-mgsin(17)0.120 Taking F=ma and solving for a I came up with F/m=a So....[mgsin(17)-mgsin(17)0.120]/m This gave me 2.52 m/s^2 Plugging that into one of my kinematic equations.... [tex]s_f = s_i +v_i + 1/2at^2[/tex] s=(.5)(2.52)(28.2^2) I ended up with the final distance as 1002m. The book answer is 692m. What am I missing?