1. The problem statement, all variables and given/known data Suppose a car starts from rest and rolls down a hill that is 50 m high. You are going to find the speed of the car at the bottom of the hill. What physics will you use to find the speed? Now find the speed. 2. Relevant equations KE= 1/2mv^2 PE= mgh Speed= distance x time 3. The attempt at a solution I am not sure where to start since there is so little information. 50m (height) x 9.8 m/s^2 (gravity)= 500 m^2/s^ but is this PE? KE? I don't have mass so I don't think its PE, and I'm sure it's not KE. What I know: its initial velocity is 0, height is 50m, since it is "falling" it is under the influence of gravity 9.8 m/s^2. If it is falling 50 m at 9.8 m/s that's 5.102 seconds "falling"? So the speed is 5.102s x 50m = 255.01 m/s? Is this correct? Am I along the right lines?