Two bodies make an elastic head-on collision on a smooth horizontal table kept in a car. Do you expect a change in the result if the car is accelerated on a horizontal road because of the non-inertial character of the frame? Does the equation “Velocity of separation = Velocity of approach” remain valid in an accelerating car? Does the equation “final momentum = initial momentum” remain valid in the accelerating car?

Question

Philoid · Accepted Answer

Yes, we can expect a change in the result of the experiment. If we look at the motion from the frame of reference of the car, the two bodies experience a pseudo force in a direction opposite to the direction of motion of the car.

Now since there is a net non-zero force on the two bodies, the momentum of the two body system is not conserved in this case.

So, the equation “final momentum = initial momentum’ does not remain valid.

Also, since the momentum of the two body system is not conserved the equation “Velocity of separation = Velocity of approach” also does not remain valid.