Page "Momentum" Paragraph 33

This law holds no matter how complicated the force is between particles.

Similarly, if there are several particles, the momentum exchanged between each pair of particles adds up to zero, so the total change in momentum is zero.

This conservation law applies to all interactions, including collisions and separations caused by explosive forces.

It can also be generalized to situations where Newton's laws do not hold, for example in the theory of relativity and in electrodynamics.