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Class 9
Science
Force and Laws of Motion
akhtar kiran and rahul were riding in a motorcar...

Question:
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:

According to the law of conservation of momentum, the momentum of a system before collision is equal to the momentum of the system after collision.

Hence, the change in momentum of the car and insect system is zero.

Thus, Kiran is wrong with the logic as momentum is always conserved, i.e change in momentum of insect must be equal to that of a motorcar.

Akhtar’s logic is incorrect because the mass of the car is very large as compared to the mass of the insect.

Rahul gave the correct logic as insects and motorcar experience the same force and change in momentum.

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