1. The problem statement, all variables and given/known data A car is coasting without friction toward a hill of height 'h' and radius of curvature 'r'. What initial speed will result in the car's wheels just losing contact with the roadway as the car crests the hill? 2. Relevant equations Kinetic Energy = (1/2)(m)(v^2) Potential Energy = mgy 3. The attempt at a solution Because the acceleration will vary with time, constant energy kinematics can't be used to solve the question. Without friction, there are no nonconservative forces acting on the system, so there is no energy lost. Therefore the kinetic energy of the car at the bottom of the hill must be equal(?) to the potential energy of the car at the top of the hill. But I can't seem to work the radius of curvature into the theory at all. There's can't be a centripidal force because the only force holding the car to the curvature of the hill is the force of gravity. I'm a little stuck at this point. Thank you in advance for any help someone can give.