1. The problem statement, all variables and given/known data An overhead view of the path taken by a ball of mass m as it bounces from the rail of a pool table. The ball's initial speed is v and the angle is a. The bounce reverses the y component of the ball's velocity but does not alter the x component. ... (b) What is the change in the ball's linear momentum in unit - vector notation? 2. Relevant equations Change in momentum (DP) DP(J) = mvcos(a)(-j^) - mvcos(a))+j^) DP(I) = mvsin(a)(-i^) - mvsin(a))+i^) 3. The attempt at a solution I know that the initial and final angles are the same. I thought I needed to use a form like this to get the answer DP(I) + DP (J) Both of my answers are negative. I'm not sure if that's the problem or if I have my sin and cos for j and i mixed up.