Newton's Third Law of Motion

Newton’s Third Law of Motion is often phrased as ‘for every action, there is an equal and opposite reaction’.

The law suggests that forces always exist in pairs. If one object exerts a force on a second object, the second object exerts an equal and oppositely directed force on the first.

Newton’s Third Law is key in understanding how movement and forces work, with forces being balanced or unbalanced.

As per Newton’s Third Law, action and reaction forces do not cancel each other out. This is because they act on different objects, hence they do not make a net force of zero together.

This law is applied in various practical scenarios such as propulsion of rockets, walking or swimming, where the object or person exerts a force on the air or water, and in turn, the air or water exerts an equal and opposite force.

Newton’s Third Law introduces the concept of conservation of momentum, as the total momentum before an event must equal the total momentum after the event. This is a direct consequence of actionreaction pairs.

Misinterpretations can occur when the system being considered is not clearly defined. To understand the context of Newton’s Third Law, it is significant to clarify that the action and reaction forces act on different objects.

Understanding this law supports further learning in topics such as momentum, pressure, and gravitational forces.