In a closed system, what can be said about momentum before and after a collision?

In a closed system, the principle of conservation of momentum states that the total momentum of the system remains constant before and after a collision, provided no external forces act upon it. This means that the total momentum calculated from all objects involved in the collision before the impact will equal the total momentum taken after the collision.

This principle is crucial in understanding how colliding bodies interact in both elastic and inelastic collisions. In elastic collisions, not only is momentum conserved but kinetic energy is also conserved. In inelastic collisions, momentum is conserved, but kinetic energy is transformed into other forms of energy, such as heat or sound. Regardless of the type of collision, the fundamental takeaway is that within a closed system, the total momentum before the collision is identical to the total momentum after the collision, reinforcing the concept of momentum conservation.