AQA GCSE Physics

Revision Notes

5.6.7 Circular Motion

Higher Tier Only

Circular Motion

  • Velocity is a vector quantity, and the velocity of an object is its speed in a given direction
  • When an object travels along a circular path, its velocity is always changing
    • The speed of the object moving in a circle might be constant – that is, it is travelling the same distance every second
    • However, the direction of travel is always changing as the object moves along the circular path
  • The image below shows an example of a famous object that moves in a circular path with a constant speed but changing direction:

ISS circular dance, downloadable IGCSE & GCSE Physics revision notes

The International Space Station’s velocity is always changing – it whizzes around the Earth at a constant speed of about 7660 m/s but is always changing direction

Exam Tip

You may be asked to explain why motion in a circle involves constant speed but changing velocity, so remember to mention that velocity is a vector quantity, so both magnitude and direction are important.

Even though the magnitude (speed) doesn’t change, its direction does – so the velocity itself is changing.

Author: Jonathan

Jonathan graduated with a first-class Master's degree in Theoretical Physics from Imperial College London. He has worked in education for more than a decade as a Maths and Physics Teacher, Tutor, Head of Physics, and most recently, as Assistant Headteacher. He is now an Educational Consultant and works with us to design and improve our Physics resources.

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