Easy problem that I'm a bit confused about.

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The discussion focuses on a physics problem involving Joe and John playing catch in space, where Joe throws a ball to John. The calculations for Joe's velocity after throwing the ball and John's velocity after catching it are presented, with Joe's velocity calculated as -0.72329 m/s and John's as 0.56489 m/s. The user seeks confirmation on whether the problem was set up correctly and asks for suggestions or clarifications. Responses indicate that the setup appears accurate and the calculations are valid. Overall, the thread emphasizes understanding momentum conservation in a closed system.
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Homework Statement



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.

Homework 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.
 
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