ForcesKey Facts

Newton's Third Law — Action-Reaction

Part of Newton's Laws of MotionGCSE Physics

This key facts covers Newton's Third Law — Action-Reaction within Newton's Laws of Motion for GCSE Physics. Revise Newton's Laws of Motion in Forces for GCSE Physics with 13 exam-style questions and 15 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 6 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 6 of 15

Practice

13 questions

Recall

15 flashcards

📜 Newton's Third Law — Action-Reaction

Statement: When object A exerts a force on object B, object B exerts an equal and opposite force on object A.

Key features of Third Law pairs:

  • Equal in magnitude
  • Opposite in direction
  • Act on DIFFERENT objects
  • Same type of force
  • Act simultaneously

Examples:

  • You push wall → wall pushes you (contact forces)
  • Earth pulls you → you pull Earth (gravitational)
  • Rocket pushes gas down → gas pushes rocket up
  • Swimmer pushes water back → water pushes swimmer forward

Keep building this topic

Read this section alongside the surrounding pages in Newton's Laws of Motion. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Newton's Laws of Motion

According to Newton's First Law, what happens to an object when there is no resultant force acting on it?

  • A. It accelerates in the direction of motion
  • B. It remains at rest or continues moving at constant velocity
  • C. It decelerates and eventually stops
  • D. It changes direction
1 markfoundation

A spaceship is travelling through deep space far from any planets. The engines are switched off. Explain what will happen to the motion of the spaceship and why.

2 marksstandard

Quick Recall Flashcards

Key Concepts
Unit: Newton metres (Nm)
Key Concepts
A moment is the turning effect of a force

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