15.5 Force on a System of Particles
Now we'd like to analyze in more depth our result that for a system of particles-- so let's indicate our system. We had particle 1. We have our jth particle. And we have a particle N. So here's our system of particles where the total force caused the momentum of the system of particles to change. Now, I'd like to examine that concept of the total force. Before we said that our total force on the jth particle-- we just wrote it like this. And I'm going to put a little t up here for the moment. Because when we examine what force we mean here-- and I also want to put a little boundary around our system. And let's now consider another particle internal to the system. And let's try to identify the types of forces on the jth particle. We can really have two types of forces here. Our first force can be an interaction between these two particles. So what I'll write is the force on the jth particle due to the interaction between the k and the jth pa...