Answer to Question #136588 in Molecular Physics | Thermodynamics for Sneha

Question

Explain third law of newton.

Answer 1

Newton's third law of motion also known as the Action-Reaction law states that "To every action there is always an equal reaction acted in the opposite direction".

What this means is that all forces between two bodies exist in equal magnitude acting in opposite directions, i.e if a body A exerts a force F_A on a second body B, then B simultaneously exerts an equal but opposite force F_B on A.

The general formula for Newton's third law is;

FA = −F_B

Examples of Newton's third law in real life scenarios are;

1. While Rowing a boat, when you want to move forward on the boat, you paddle by pushing the water backwards, causing you to move forward

2. In a rocket, fuel is burnt, to create exhaust gas which pushes downwards with a particular force. This creates an equal and opposite push making the rocket move in the upward direction.