Hi All, I conducted some experiments on snooker balls and am trying to find the coefficient of restitution between the balls. For the sake of the experiment, I have stated that the balls are sliding rather than rolling, and from an earlier experiment, I have discovered that there is a constant deceleration on the balls of 0.165m/s^2 due to friction(again I have assumed that this deceleration is caused by the force of friction between the ball and the table as the ball slides rather than air resistance or rolling friction). I calculated the velocities of the balls immediately before and after collision. The white ball was moving whereupon it collided with the pink ball which was at rest. Using the distances travelled by the balls after collision in the same direction as the original motion and taking into account the deceleration, I used v^2=u^2+2as and my results were as follows: Using v1-v2=-e(u1-u2) I have calculated the coefficient of restutution to be 0.359. I'm probably being very silly here, but given that the pink travels at a velocity of 0.419m/s after the white hits it at a velocity of 0.613m/s, shouldn't e be a little higher? I plan to use my result for e to state the minimum velocity the white should be travelling at in a different shot to pot the pink ball, but am now confused as to whether this is possible. This is all very simplified, but I have to do a presentation on this very soon and any help would be greatly appreciated!