PS.2.2 Worked Example - Stacked Blocks - Free Body Diagrams and Applying Newtons 2nd Law
One of the big difficulties students have in a problem that involves many objects is to successfully identify third law interaction pairs. So today, I'd like to look at a problem which shows us how to think about that. So what we're going to look at is third law interaction pairs. Now, the problem I'd like to consider is the following. Suppose we have a block one and another block two sitting on block one on a surface and our surface has friction. And I'd like to push block one with a force F. And now I'd like to use Newton's second law to determine what is the maximum force I can push that block two will not slip. So I'm trying to find F max such that block two does not slip. Now, how do we even begin to think about this? Well, the first thing that we have to decide is when we apply Newton's second law, our first question will be, what is the system that we'll choose? And in this problem, there are three separate ways to think about th...