Question

Car A rear ends Car B, which has twice the mass of A, on an icy road at a speed low enough so that the collision is essentially elastic. Car B is stopped at a light when it is struck. Car A has mass m and speed v before the collision. After the collision.. A)each car has half the impulse of before B)each car has double the impulse of before C)each car have the same impulse D)each car has an impulse in ratio to its mass.

Answer 1

We are given the following information.

The collision is elastic.

Car B has twice the mass of car A.

Recall that in an elastic collision, the momentum and the kinetic energy are conserved.

Impulse is basically the change in momentum.

Since car B has 2 times the mass of car A, the momentum of car B will be 4 times the momentum of car A.

This means that the impulse of car B will be greater than the impulse of car A.

Option D says that each car has an impulse in ratio to its mass meaning that a car with a larger mass will have a larger impulse and vice versa.

Therefore, we can conclude that after the collision, each car has an impulse in ratio to its mass.