Physics (11th and 12th) by Er GK Singh

Newton's Third Law of Motion

Statement:
"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 on the first object.

Mathematical Representation:

If object A exerts a force F on object B, then object B exerts a force -F on object A:

F(AB)= -F(BA)

Equal in magnitude

Opposite in direction

Acting on different objects (Action and Reaction forces never cancel out each other because they act on different bodies)


Examples:

1. Walking – When you push the ground backward with your foot, the ground pushes you forward with an equal force.


2. Rocket propulsion – The rocket pushes gases downward, and the gases push the rocket upward.


3. Jumping off a boat – When you jump forward from a boat, the boat moves backward.


4. Recoil of a gun – When a bullet is fired forward, the gun moves backward with an equal and opposite force.

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