A car moves at a constant speed on a straight but hilly road. One section has a crest (peak) and dip of the same 250-m radius, as shown in the figure below.
 (a) As the car passes over the crest, the normal force on the car is one-half the 16-kN weight of the car. What will be the normal force on the car as it passes through the bottom of the dip?
 (b) What is the greatest speed at which the car can move without leaving the road at the top of the hill?
 (c) Moving at the speed found in (b), what will be the normal force on the car as it moves through the bottom of the dip?