Question

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 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 1

☆$\red {HELLO\:DEAR}$☆

According to the law of conservation of momentum:

Momentum of the car and insect system before collision = Momentum of the car and insect system after collision

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

The insect gets stuck on the windscreen. This means that the direction of the insect is reversed. As a result, the velocity of the insect changes to a great amount. On the other hand, the car continues moving with a constant velocity. Hence, Kiran’s suggestion that the insect suffers a greater change in momentum as compared to the car is correct. The momentum of the insect after collision becomes very high because the car is moving at a high speed. Therefore, the momentum gained by the insect is equal to the momentum lost by the car.

Akhtar made a correct conclusion because the mass of the car is very large as compared to the mass of the insect. Rahul equal to the momentum after the collision.

☆$\green {VISHU\:PANDAT}$☆

☆$\blue {FOLLOW\:ME}$☆

Answer 2

$\huge{\underline{\underline{\boxed{\sf{\orange{Answer ࿐}}}}}}$

Rahul gave the correct reasoning and explanation that both the motorcar and the insect experienced the same force and a change in their momentum. As per the law of conservation of momentum.

When 2 bodies collide:

Initial momentum before collision

= Final momentum after collision

m1 u1+ m2 u2

= m1 v1+ m2 v2

The equal force is exerted on both the bodies but, because the mass of insect is very small it will suffer greater change in velocity.