The Momentum of a System with Two balls

The total momentum can be found by adding the momentums of each ball. Momentum is calculated by multiplying the mass of an object by its velocity (Momentum = mass x velocity). So the momentum of the first ball is 0.5 kg x 6 m/s = 3 kg•m/s to the right, and the momentum of the second ball is also 0.5 kg x 6 m/s = 3 kg•m/s but to the left. Since they are moving in opposite directions, we subtract one from the other to get the total momentum. However, as both are equal in magnitude but opposite in direction, they cancel each other out, which means the total momentum of the system is 0 kg•m/s. This does not mean there is no motion, but rather that the system is balanced in terms of momentum. The magnitude of the total momentum is therefore zero.