Key Stage 4
Meaning
A reaction force is a force which acts in the opposite direction to an applied force, following Newton's Third Law.
About Reaction Force
- Newton's Third Law states that "For every action force there is a reaction force with an equal magnitude but acting in the opposite direction".
- The terms 'action force' and 'reaction force' may sometimes be misleading as forces always act in pairs.
- If weight is considered to be the action force then the normal contact force of an object on the ground can be considered the reaction force.
- If there were no weight the object would not stay in contact with the ground so the reaction force would not longer exist without the action force.