question_answer 17)

Akhtar, Kiran and Rahul were riding in a motorcar that was moving with 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. 

Answer:

Kiran's suggestion is incorrect as momentum is always conserved, i.e., change in momentum of insect must be equal to that of motorcar. Akhtar's suggestion is incorrect for the same reason as above. Rahul's suggestion is correct, i.e., insect and motor-car experience same force and change in momentum. However, the insect dies because, it is unable to bear the large force and large change in momentum.