Mastery Check #1 - Newton's 1st and 2nd Laws of Motion
Isaac Newton wanted to understand why objects on Earth and in space moved the way that they did. After many observations and experiments, he came up with three laws of motion that described accurately the motion of objects
Newton's 1st Law of Motion
An object in motion will stay in motion unless acted upon by an outside force and an object at rest will stay at rest unless acted upon by an outside force. In other words, an object will keep doing what it's doing unless a force makes it speed up, slow down or change directions. This includes if the object is not moving - it will keep still unless a force makes it move (picture #1). This is also known as inertia. This was revolutionary because people used to think that the planets had a force constantly pushing them around the sun. This explained how planets could just keep moving around the sun unless something slowed them down. On Earth's surface we don't often see this because there is almost always friction that slows down moving objects. We can, however, see many examples of this happening on Earth. Here are a few:
|
|
Newton's 2nd Law of Motion
Objects accelerate according to their mass and the force applied to them. The bigger the force applied to them, the faster they will accelerate. The bigger their mass, the harder it will be to accelerate them. This can be described with a mathematically as F = MA. If you were to push with the same force on two objects with different masses, the one with the smaller mass will accelerate more (picture #1). Here are some examples of the 2nd law of motion:
|
|
Here are some videos explaining these laws of motion:
|
|