1. The problem statement, all variables and given/known data Picture looks like this: ----------------------- ○ (empty space) ● (Cue) (White ball) (Black Ball) Mass: Cue (595g), White Ball (170g), Black Ball (155g) Question: On the given pool table, the white ball bounces off of the black ball and moves in the direction opposite to its original direction. If the speed of the white ball immediately after the collision is 3.13m/s, then the speed of the black ball immediately after the collision is _______m/s. (Record your three-digit answer) 2. Relevant equations Conservation of Momentum Pi=Pf 3. The attempt at a solution 0=(-3.13m/s)×(170g) + (155g)×V 532.1kgm/s = 155g×V V= 3.43m/s Apparently this is not the answer... What am I doing wrong?? 4. Keybook Solution Pi=Pf MV (1) + MV (2) = MV'(1) + MV'(2) 170g×(3.13m/s) + 0 = 170g×(-0.147m/s) + (155g)V '(2) V'(2) = 3.59m/s How do you get (-0.147m/s)???