Newton's Laws of Motion/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.

As Isaac Newton himself 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.

Also known as

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

It is also often referred to as just Newton's third law.

Also see

• Newton's First Law of Motion
• Newton's Second Law of Motion

Source of Name

This entry was named for Isaac Newton.

Sources

• 1937: Eric Temple Bell: Men of Mathematics ... (previous) ... (next): Chapter $\text{VI}$: On the Seashore
• 1965: J.W. Leech: Classical Mechanics (2nd ed.) ... (previous) ... (next): Chapter $\text {I}$: Introduction: $(3)$
• 1966: Isaac Asimov: Understanding Physics ... (previous) ... (next): $\text {I}$: Motion, Sound and Heat: Chapter $3$: The Laws of Motion: Action and Reaction
• 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): Entry: Newton's laws of motion