Akhtar, Kiran and Rahul were riding in a motorcar that was a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen . Akhtar and Kiran started pondering over the situation. Kiran suggested that the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar (because the change in the velocity of the insect was much more than that of the motorcar). Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect. And as a result, the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum. Comment on these suggestions.

Explanation

Rahul's explanation is correct due to the following reasons:
(i) When insect hits the wind shield of the car, it exerts a force on wind shield and according to Newton's third law wind shield will exert equal force on the insect but in opposite direction. Thus, both the motor car and insect experienced the same force.
(ii) According to conservation of momentum, during collision, the total momentum of the system remains conserved. It means the change in momentum of the car should be equal and opposite to that of the insect. Since the momentum is the product of mass and velocity of the body, the insect having smaller mass will suffer greater change in velocity resulting in greater injuries or even death. Whereas motor car having very large mass will suffer very small change in velocity.