Lesson 4: Newton's Law of Equal and Opposite Reactions, the Third Law!

This is what Newton's third law is about.

Newton’s Third Law of Motion

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

The actions and reactions in Newton's third law are forces. You can use this law to figure out how forces move an object with a known mass.

Whenever one object puts a force on a second object, the second object applies the same force in the opposite direction.

You can write this as a formula:

If object A puts a force on object B (F_{A on B}),

then object B puts an equal amount of force on object A, but in the opposite direction (-F_{B on A})

F_{A on B} = -F_{B on A}