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Newton’s Third law Of Motion | Formula & Examples In Everyday Life

Newton’s Third Law of Motion 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 force in the opposite direction.

Newton's Third law Of Motion

What is Newton’s Third Law Of Motion?

Principle of action and reaction:

The postulate of Newton’s third law says that every action generates an equal reaction, but in the opposite direction.


The force of body 1 on body 2 (F 1-2) , or action force, is equal to the force of body 2 on body 1 (F 2-1) , or reaction force. The reaction force will have the same direction and magnitude as the action force, but in the opposite direction to it.

An example of Newton’s third law is when we have to move a sofa, or any heavy object. The action force applied to the object causes it to move, but at the same time it generates a reaction force in the opposite direction that we perceive as a resistance of the object.

Everyday Life Examples Of Newton’s Third Law Of Motion

Here are main everyday life examples of this law is given below:

  1. Walking:
    • When you walk, your foot exerts a backward force on the ground (action). In response, the ground exerts an equal and opposite forward force on your foot (reaction), propelling you forward.
  2. Swimming:
    • As you swim, your hand pushes the water backward (action). Simultaneously, the water exerts an equal and opposite force on your hand, pushing it forward (reaction).
  3. Driving a Car:
    • The tires of a car push backward against the road (action) when the car accelerates. Simultaneously, the road exerts an equal and opposite forward force on the tires (reaction), propelling the car forward.
  4. Rocket Propulsion:
    • In a rocket, hot gases are expelled backward at high speeds (action). As a result, the rocket experiences an equal and opposite forward thrust (reaction), causing it to move forward.
  5. Airplane Flight:
    • The engines of an airplane expel air backward (action). In response, the airplane experiences an equal and opposite forward thrust (reaction), allowing it to move through the air.


Newton’s Third Law highlights the mutual interaction between two objects. The forces may be of different types (e.g., gravitational, contact forces), but they are always equal in magnitude and opposite in direction. Understanding this law is crucial for analyzing and predicting the motion of objects in various situations.

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