Action and Reaction force

Action and Reaction force

A book placed on a table exerts a force (equal to weight of the book) on the table.

This force is called action. In response to the action, an equal force is exerted in opposite direction by the table on the book such a responding force is called reaction.

Book placed on table

Space shuttle

The space shuttle engines push out hot gases as an action force and the hot gases exert a reaction force on the shuttle engines which makes the shuttle lift up.

A space shuttle

In both the above mentioned examples; action and reaction are two equal forces, but their directions are opposite. Newton explains this kind of force in a law which is known as the third law of motion. This law is stated as;

                        “To every action, there is an equal and opposite reaction”