Question

In an elastic collision, an object with momentum of 25kg.m/s collided with another object with a momentum of 35kg.m/s moving to the right. After collision both objects are still moving to the right. But the first object’s momentum is now 10kg.m/s. What is the final momentum of the second object?

Answer 1

This is a situation about momentum conservation.

The total momentum of both objects must conserve, the, total momentum before collision and total momentum after collision must be equal:

p before = p after

p1 + p2 = p1' + p2'

where p1 and p2 are the momenta of both objects before the collision. p1' and p2' are the momenta of the same both objects after the collision.

p1 = 25kg.m/s

p2 = 35kg.m/s

p1' = 10kg.m/s

p2' = ?

In order to calculate the value of the momentum of the second object after the colliwion you solve the equation for p2', as follow:

p1 + p2 = p1' + p2'

p2' = p1 + p2 - p1' replace the values of all parameters

p2' = 25kg.m/s + 35kg.m/s - 10kg.m/s

p2' = 50kg.m/s

Hence, the final momentum of the second object is 50kg.m/s