In the rather basic physics class I'm in we just coverd conservation of momentum. We went over the application of this with elastic collisions. I understand that Total momentum before the collision = Total momentum afterwards. What I dont uderstand is how can you tell what the individual momentums will be afterwards. For example: 2 objects fly directly twords eachother. Both objects are 5kg and they each are going at 5m/s. Thus the momentum of one of the objects is 25kgm/s and the other -25kgm/s. Total momentum in the system is 0. After they collide, each could move away from eachother at 5m/s or 1000m/s or 5434676m/s, the total momentum in the system would still be 0. Obviously in the real world only one of these would be accurate...so what am I missing, how do you finish the problem?