Newton’s 3rd law of motion says: for every action, there is an equal and opposite reaction.

Quick Scoop: Core Idea

  • When one object pushes or pulls another, the second object pushes or pulls back with a force that is equal in size but opposite in direction.
  • These forces always come in pairs, often written as F⃗AB=−F⃗BA\vec{F}{AB}=-\vec{F}{BA}FAB​=−FBA​.

Example:

  • You sit on a chair: you push down on the chair, and the chair pushes up on you with the same force, in the opposite direction.

Everyday Examples

  • Walking: Your foot pushes backward on the ground; the ground pushes you forward, letting you move.
  • Rocket or jet: Exhaust gases are pushed backward; the rocket or jet is pushed forward.
  • Skateboard: You push the ground backward with your foot; the reaction force moves you and the board forward.
  • Bird or fish: Bird wings push air down, air pushes the bird up; fish fins push water back, water pushes the fish forward.

Why It Matters Now

  • This law underlies how rockets, planes, cars, and even simple tools like door handles work, so it’s still central in engineering and space tech today.
  • Modern physics and simulations still build on Newton’s laws, especially for game engines and basic robotics where action–reaction force pairs are crucial.

In short: any time you see motion caused by a push or pull, you’re seeing Newton’s 3rd law in action, with hidden force pairs working behind the scenes.

TL;DR: Newton’s 3rd law = forces come in equal-and-opposite pairs, so no object can push without being pushed back.

Information gathered from public forums or data available on the internet and portrayed here.