1. A car of mass 1500kg moving at constant speed of 80km/hr passes over a humpback of a bridge of radius of curvature r. The car remains in contact wit the road as it passes over the top. a) Express N, net force exerted by the car on the road, in terms of r. b) Determine the minimum curvature required of the car to just remain in contact with the road. Generally i do understand the basic concept behind the questions, where [Weight of Car - Normal Reaction of the road on the Car] = Result Force = Centripetal Force But why is that the case? Why is it that Mg is greater than NR? If it is different, we can see Mg is not the force exerted on the road by the car. So what is the force exerted by the car on the road that causes the Normal Reaction on the car by the road. Is it a component of the weight? Where does the force come from?