Physics Question-A 2500 kg rollercoaster is at the top of a 75 m hill traveling at 25.0 m/s.?

It then travels down the frictionless hill to the bottom, 75 m below. a. With what speed does the coaster reach the bottom of the hill? b. IF the track is flat when the coaster gets down to the bottom, and then comes to rest uniformly over a distance of 100 m, what is the total resistive force (friction + air resistance) acting on the coaster?