PHYS 2001 Chapter : PHYS2001 Lect16
Document Summary
We talked last time how newton"s laws naturally show up in our discussions of momentum. Force equals the rate of change of momentum: action equals reaction: *changes in the momentum are of equal magnitude and in opposite directions! Let"s just consider the simplest interacting system that we can. Such a system will consist of two particles, m1 and m2, interacting with each other. Assume for now that the two particles form an isolated system from the rest of the universe, and the only forces they experience are their mutual forces. m2. In other words, there are no external forces. Let the net force on particle 1 by 2 be f. Then by newton"s 3rd law, we know that the net force on particle 2 is f. Now let"s add these two equations together. m1. ,0= where , the total momentum. pp p. In other words, it is a constant of the motion! This is the law of conservation of momentum.
