1. The problem statement, all variables and given/known data Well I need to find the acceleration of a pool ball after it has been hit by the cue. I measured the final velocity of the cue which was 2.9m/s and its acceleration was 41.42m/s*2. I know that the vf of the cue is the vi of the ball and because the ball has friction after it has had the force applied, the acceleration should be a negative value but it keeps coming positive and pretty large too. OF CUE: Vi=0m/s t=.07s d=.1016m Used d=1/2(Vi+Vf)t to find Vf rearranged to vf=2d/t-Vi OF BALL: Vi=2.9m/s t=.118s d=.5588m Used the ball values for equation below 2. Relevant equations d=Vit+(1/2)at*2 3. The attempt at a solution rearranging for a I get 2(d-(Vi t )) all divided by t*2=a Substituting values in I get 2(.5588m-(2.9m/s x .118s) divided by .118s*2 That turns into 2(.5588-.3422)/.0139s and once finished I got 31.16m/s*2 as my acceleration. But if that is the case then my Vf of the ball will be greater than the Vi and that wouldn't make sense considering its on a horizontal surface and friction is being applied. Did I make a mistake in the calculations or values. ANY help would be appreciated, thanks in advance.