A 1030 kg roller coaster goes over hill and through a valley, then upside down on a loop. The radius of the first hill circular path is 8 meters and the velocity over this hill is 3m/s. The radius of the valley is 18 meters. The velocity at the bottom of the valley is 9m/s. What is the centripetal force at the top of the first hill? what is the normal force at the bottom of the valley? if the magnitude of normal force at the top of the hill 3200 what is the velocity? what is the total mechanical energy?