Suppose a car moves at constant speed along a mountainroad. At

what places does it exert the greatest and leastforces on the road:

(a) at the top of a hill, (b) at a dip betweentwo hills, (c) on a

level stretch near the bottom of a hill?

Answer: (b) At a dip between two hills

(a) At the top of the hill

Explanation:This situation can be explained using Newton's third Law of motion. This Law states that action and reaction are equal and opposite.

The force exerted by the car on the road is highest at the dip. The force exerted by car on the dip will be highest in response to the reaction from the two hills, the car will have to give enough force to equal the force given by the end of a previous hill and that given by the starting of the other hill.

The force exerted by the car will be lowest at the top of the hill, this is mainly because the car has a maximum centripetal downward force at the crest of the hill, The car has less need to exert any force on the road.