In a game of pool why will the balls eventually stop after a collision

Everything we see happening on Earth has friction along with it.

For a pool ball, it's the work the ball does bending all the little cloth

fibers out of the way as it rolls along the table, and also the work it

does pushing air out of the way. These things rob a little bit of each

ball's kinetic energy, so that it eventually stops rolling.

Note: Gravity is not the answer.