1. The problem statement, all variables and given/known data You have Joe and John playing catch in space. Joe throws the ball to John with a velocity of 7.5 m/s. Given Variables Joe's mass is 60.9 kg John's mass is 79.8kg Ball's mass is 6.5kg Find: A) Joe's velocity after he throws the ball. B) John's velocity after he catches the ball. 2. Relevant equations Sum of the external forces = 0; Psys=0 For A, I used: (Mass of ball+ Mass of Joe) (Velocity of Joe after he throws the ball) + (Mass of ball)(Velocity of Ball) = 0 I ended up with: Velocity of Joe after he throws the ball = - [(Mass of ball)(Velocity of ball)]/(Mass of Ball + Mass of Joe9) After substituting in the numbers, the velocity of Joe is: -.72329 m/s For B, I used: (Mass of Ball)(Velocity of Ball) = (Mass of John + Mass of Ball)(Velocity of John after he catches the ball) The Velocity of John after he catches the ball is: .56489m/s Did I set this problem up properly? Any suggestions or clarification would be greatly appreciated. Thanks.