Newton’s second law says that to speed up or slow down an object, you have to use a force. But first…

Q. What’s a force?

A. Simple. A force is just a push or a pull.

Q. But what about a kick? Or a throw?

A. A kick is just pushing something with your feet. And a throw is pushing something with your fingertips. Do you remember how Isaac Newton discovered gravity? Gravity is a force, too – it is a pull. And it pulled the apple right down onto Newton’s head. We have lots of names for pushes and pulls. Scientists call forces away from the start a push and towards the start a pull.

Just remember that all forces are pushes or pulls.