1. The problem statement, all variables and given/known data A 1.50 kg toy rollercoaster rests on a ramp of height h. When the toy rollercoaster is released, it slides without friction to the bottom of the ramp, and then continues on a flat surface with a rough patch of width 10.0 cm that has a coefficient of kinetic friction µk = 0.770. Find h such that the toy rollercoaster's speed after crossing the rough patch is 3.50 m/s. 2. Relevant equations K = 1/2mv^2 U = mgh 3. The attempt at a solution Kf = 1/2mv^2 = 1/2(1.5kg)(3.5 m/s)^2 Kf = 9.188 fk = ukN = .77(mg) = 11.319 (multiplied by the distance of .1m = 1.132) I can't do mgh because I don't know h. I know I probably need to figure out how fast the toy roller coaster was going right before it hit the rough patch, but I can't seem to figure that out without knowing "h" so I am stuck here with no idea where to go.