The third law of motion, formulated by Sir Isaac Newton, states that for every action, there is an equal and opposite reaction. This means that whenever one object exerts a force on a second object, the second object exerts an equal and opposite force back on the first object. This law applies to all interactions between objects, whether they are in contact or not.

Example 1: Rocket Propulsion

A classic example of Newton's third law is seen in rocket propulsion. Rockets work by expelling high-speed gases out of their engines in one direction, which generates a force pushing the rocket in the opposite direction. The expelled gases are the action force, while the resulting motion of the rocket is the reaction force.

Example 2: Ball Bouncing

When a ball is thrown onto a solid surface, it bounces back. As the ball hits the ground, it exerts a force on the surface, causing the surface to exert an equal and opposite force on the ball, propelling it back up.

Example 3: Swimming

Swimming provides another illustration of Newton's third law. As a swimmer pushes against the water with their arms and legs, they experience a reaction force in the opposite direction, propelling them forward.

Understanding and applying Newton's third law is crucial for various fields, including physics, engineering, and sports. By recognizing the action-reaction pairs in various scenarios, we can analyze and predict the behavior of objects and systems more accurately.