# Newton's laws of motion - Mnemonic

An easy way to remember Newtons three laws of motion is given below and will enable you to recall the laws.

## 1st Law

One day Newton was walking by a field when he saw a cow grazing.

He kicked the cow and because it hurt her (inertia) she walked a few metres.

With this he concluded:

A thing will not change its state of motion or rest unless an external force acts on it.
Thus the 1st law. Known as the law of inertia.

## 2nd Law

He kicked the cow again and the cow screamed MAAAAA.

With this he concluded:

A force applied is equal to mass times acceleration.
F=ma

## 3rd Law

Newton kicked the cow for a third time but this time the cow kicked Newton back with an equal and opposite force. And then kicked him with the other leg to remind you that for every interaction forces are found in pairs.

With this he concluded:

For every action, there is an equal and opposite reaction.

For every interaction, forces are found in pairs.

NOTE: Newton didn't really kick cows but this is a great mnemonic for remembering his laws.