Two friends, Al and Jo, have a combined mass of 151 kg. At an ice skating rink they stand close together on skates, at rest and facing each other, with a compressed spring between them. The spring is kept from pushing them apart, because they are holding each other. When they release their arms, Al moves off in one direction at a speed of 1.23 m/s, while Jo moves off in the opposite direction at a speed of 0.799 m/s. Assuming that friction is negligible, find Al's mass. I know that: m1 + m2 = 151 V(Al) = -1.23 V(Jo) = .799 m1 = 151 - m2 m1v1 = m2v2 but don't know how to separate the masses. Can anyone guide me through that process? Greatly appreciated.