Look around and find something that's moving. Why is it moving? Just for fun? Now look at something that's not moving. Why is it not moving? Because it doesn't feel like it? Now that we've learned about how things move in kinematics, we can learn about why things move (or don't move).
This is the part of physics where things get a little more interesting. Things are happening all around you and you probably never gave a second thought about why they happen. As we start to learn about what's really going on, some things will be much more complex than you imagine, and some things will be way simpler.
We can see motion, but we can't really see the forces affecting that motion. If you roll a ball across the ground, you know it's going to slow down and stop because that's what things do. If you drop a pen, you know it's going to fall down and hit the floor because that's what things do. If you place a book on a table, you know it's not going to move because that's what things do.
But as we learn more about physics, try to set aside your intuitions about "what things do". We're going to build new intuitions about why things happen, intuitions that are based on the fundamentals of physics. Then we can understand anything in the universe, not just rolling balls and falling pens.
This lesson will start us off by introducing Newton's 1st and 2nd Laws of Motion. These will help us understand how the forces acting on an object determine that object's motion (or lack of motion). The famous equation that we get from Newton's 2nd Law, F = ma, is the foundation for this section and a lot of physics.
Things start to get a little complicated when we have many forces acting on an object, especially if the object is moving. That's where free body diagrams come in. A free body diagram (FBD) (also known as a force diagram) is a picture that isolates a single object (or a system) and shows all of the forces acting on that object. Forces are vectors so we represent them in the free body diagram with arrows that show their direction. Even if we think we know what's going on with an object, it's not until we actually draw a free body diagram and list each force that we can know for sure. This will help keep things organized as we solve a problem.
Answers
- Newton's 1st Law of Motion
- Newton's 2nd Law of Motion
- Free body diagrams
Look around and find something that's moving. Why is it moving? Just for fun? Now look at something that's not moving. Why is it not moving? Because it doesn't feel like it? Now that we've learned about how things move in kinematics, we can learn about why things move (or don't move).
This is the part of physics where things get a little more interesting. Things are happening all around you and you probably never gave a second thought about why they happen. As we start to learn about what's really going on, some things will be much more complex than you imagine, and some things will be way simpler.
We can see motion, but we can't really see the forces affecting that motion. If you roll a ball across the ground, you know it's going to slow down and stop because that's what things do. If you drop a pen, you know it's going to fall down and hit the floor because that's what things do. If you place a book on a table, you know it's not going to move because that's what things do.
But as we learn more about physics, try to set aside your intuitions about "what things do". We're going to build new intuitions about why things happen, intuitions that are based on the fundamentals of physics. Then we can understand anything in the universe, not just rolling balls and falling pens.
This lesson will start us off by introducing Newton's 1st and 2nd Laws of Motion. These will help us understand how the forces acting on an object determine that object's motion (or lack of motion). The famous equation that we get from Newton's 2nd Law, F = ma, is the foundation for this section and a lot of physics.
Things start to get a little complicated when we have many forces acting on an object, especially if the object is moving. That's where free body diagrams come in. A free body diagram (FBD) (also known as a force diagram) is a picture that isolates a single object (or a system) and shows all of the forces acting on that object. Forces are vectors so we represent them in the free body diagram with arrows that show their direction. Even if we think we know what's going on with an object, it's not until we actually draw a free body diagram and list each force that we can know for sure. This will help keep things organized as we solve a problem.
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