Question

Imagine two billiard balls on a pool table. Ball A has a mass of 2 kilograms and ball
B has a mass of 3 kilograms. The initial velocity of ball A is 9 meters per second to
the right, and the initial velocity of the ball B is 6 meters per second to the left. The
final velocity of ball A is 9 meters per second to the left, while the final velocity of
ball B is 6 meters per second to the right.
1. Explain what happens to each ball after the collision. Why do you think this
occurs? Which of Newton’s laws does this represent?
2. What can you say about the total momentum before and after the collision?
3. What do you think would happen to the velocity of each ball after the collision if the masses and initial velocities of each ball were the same?

Answer 1

use conservation of momentum. that's always conserved.

Answer 2

Thanks, but I am really confused about all of this. I dont understand at all.

Answer 3

Well, for starters, "Explain what happens to each ball after the collision" is a meaningless question. Who knows? They get abducted by aliens?

I think they might wish you to notice the symmetry. It is always good to draw the situation, before and after. Then you will understand what i mean by symmetry.....

Answer 4

.....but overall they seem keen for you to calculate the momentum before and after the collision. but you should also look at the kinetic energy before and after, as well.