12.1 Pulley Problems
Let's look at a typical application of Newton's second law for a system of objects. So what I want to consider is a system of pulleys and masses. So I'll have a fixed surface here, a ceiling. And from the ceiling, we'll hang a pulley, which I'm going to call pulley A. And this pulley will have a rope attached to it, wrapped around it. And here we have object 1. And the rope goes around the pulley. And now it's going to go around another pulley B and fixed to the ceiling. So that's fixed. And hanging from pulley B is another mass 2. And our goal in applying Newton's second law is to find the accelerations of objects 1 and 2. Now, how do we approach this? Well, the first thing we have to do is decide if we're going to apply Newton's second law, what is the system that we'll apply it to? And there's many different ways to choose a system. When we look at this problem, we'll have several different systems. So let's consi...