# Momentum and Collisions - Mission MC5 Detailed Help

 The magnitude of the before- and after-collision momentum of two colliding objects are shown in the diagram below. The direction of the momentum is indicated by the arrows. The total momentum of the system before the collision is ____ kg•m/s. The total momentum of the system after the collision is ____ kg•m/s.
 The law of momentum conservation (see Know the Law section) is all about comparing the total momentum of the system before the collision to the total momentum of the system after the collision. This question provides a great introduction to the meaning of the total momentum of the system. Read on!    The total momentum of the system is the sum of both objects' momentum. In the diagram, the individual momentum values are listed. Determining the total momentum of the system is a simple matter of adding the momentum of each individual object. Since the momentum direction is rightward in each case, there is no need to consider the +/- nature or vector nature of momentum when summing individual values.
 The Law of Momentum Conservation: If a collision occurs between object 1 and object 2 in an isolated system, then the momentum change of object 1 is equal in magnitude and opposite in direction to the momentum change of object 2. In equation form m1 • ∆v1 = - m2 • ∆v2   The total momentum of the system before the collision (p1 + p2) is the same as the total momentum of the system of two objects after the collision (p1' + p2'). That is   p1 + p2 = p1' + p2' Total system momentum is said to be conserved for any collision occurring in an isolated system.