# Newton's laws of motion

Newton's laws of motion as a Venn diagram.

Newton's laws of motion are three fundamental laws describing the dynamic behavior of objects (see dynamics),
first published by Isaac Newton in his great work *Principia* in 1687. They are as follows:

## 1st law

A body will remain in a state of rest or uniform motion unless acted upon by a net external force. The first law is also called the "law of inertia" because it enshrines the concept of inertia as developed by Galileo.

## 2nd law

The net force on a body is equal to the product of the body's mass and its acceleration (i.e., the rate of change of momentum). Acceleration and force are vectors. In the second law, the directions of the force vector and the acceleration vector are the same.

## 3rd law

When two bodies interact, the force on the first due to the second is equal and opposite to the force on the second due to the first. In other words, action and reaction are equal and opposite. (See also D'Alembert's principle).