1. The problem statement, all variables and given/known data A 1300 kg car is travelling at 25 m/s as it passes the crest of a hill that has a radius of curvature of 120m. Determine the normal force acting on the car at the crest of the hill. 2. Relevant equations 3. The attempt at a solution I know that for horizontal surfaces the Normal Force is equal and opposite to the force of gravity. So I figured out the force of gravity (mg) but am unsure if this is right because I am not sure if this is a horizontal surface in the question. The question does mention the crest of a hill so do I treat this like a vertical circular motion question?