 Welcome to Unit 2 of Sino.org's Mechanics One course. In this unit, we're going to be talking about solid analysis or what happens when forces act upon objects when they push or pull or bend or twist. And all of that even depends on different kinds of properties like shape or temperature or location. So you can think about the difference between trying to twist a piece of soft clay and trying to twist a hardened brick. We're also going to be talking about stress and strain, the result of force acting upon an object. So think about what happens when someone twists or pulls on or bends your arm. All of those actions are different examples of kinds of stresses and strains. But for our purposes, we're going to be focusing more on simple objects like blocks and beams and rods. Now as we move through the course, think about how forces act upon structures in your everyday life. Think about what happens when you squeeze a grape or what happens when you stretch a piece of dough. Keep your eyes open and see what you find. Now before you get started, there's a couple things I'd like to remind you of. First, this unit will take about 35 or 40 hours to complete. And the readings here are a little bit more dense than what you probably encountered in Unit 1. So take your time, take notes, try to visualize what's going on. If that helps to make diagrams, draw pictures, go ahead and do that. And second, there will be an end of unit assessment. Of course, it's not graded, but it will help you get ready for your final exam. I will see you back at the beginning of Unit 3. Good luck.