Newton's Third Law

Physical Law

Newton's third law of motion is one of three physical laws that forms the basis for classical mechanics.

Statement of Law

To every force there is always an equal and opposite force. That is, the forces of two bodies on each other are always equal and are directed in opposite directions.

This law is also referred to as the law of action and reaction.

Also see

• Newton's First Law
• Newton's Second Law

Source of Name

This entry was named for Isaac Newton.

As he put it:

"Whenever one body exerts a force on a second body, the second body exerts a force on the first body. These forces are equal in magnitude and opposite in direction."

Sources

• Isaac Asimov: Understanding Physics (1966): $\text{I}$: Chapter $3$