Imagine two billiard balls on a pool table. ball a has a mass of 7 kilograms and ball b has a mass of 2 kilograms. the initial velocity of the ball a is 6 meters per second to the right, and the initial velocity of the balloon b is 12 meters per second to the left. when the two balls hit each other, what will happen if it is a perfectly inelastic collision? what can you say about the total momentum before and after the collision?