1. The problem statement, all variables and given/known data In outer space rock 1, with mass 6 kg and velocity < 4100, -2900, 3200 > m/s, struck rock 2, which was at rest. After the collision, rock 1's velocity is < 3900, -2400, 3700 > m/s. What is the final momentum of rock 2 (p2f)? 3. The attempt at a solution ok from my understanding of head on collision of non equal masses (honestly the problem deosnt tell me if they are equal masses or not so i assumed they are not. so i got p2f = 2p1i that is the final momentum of rock 2 is equal to twice the initial momentum of rock 1. so initial momentum of rock one = 6 * < 4100, -2900, 3200 > = <24600,-17400,19200> so the final momentum of rock 2 would be 2*<24600,-17400,19200> =<49200,-34800,38400>, but its telling me wrong answer. anything am doing wrong. Thanks.