If you want motion, you have to add force. But once you get something moving, what makes it stop? That is force, too!
Whew! Thank goodness we have simple machines. They make really hard jobs a little easier.
Isaac Newton figured out a lot of important rules about motion, and inertia is the first one.
You have heard of a car accelerating, right? Well, the same word can be used for any object. Here is how acceleration works!
Every action has an equal and opposite reaction. Newton's third law of action and reaction explains how objects affect each other when they collide. See how it works!
There is a special force of attraction that keeps our planet together. Do you know what it is?