Question

Two billiard balls of equal mass are traveling straight toward each other with the same speed. They meet head-on in an elastic collision. What is the total momentum of the system containing the two balls before the collision? What about after the collision?

Answer 1

Answer:

0 kg m/s before and after collision

Explanation:

Let m, v be the mass and speed of the 2 balls, respectively, before the collision. Since they have the same mass and same speed but in opposite direction, the total momentum of the system would be:

P = mv - mv = 0 kg m/s

As the collision is elastic. The total momentum after the collision is the same as the total momentum before the collision, which is 0.