Gravitation
Gravity is the force of attraction between all masses, which holds planets in orbit and gives objects weight.
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Gravity is the force of attraction between all masses, which holds planets in orbit and gives objects weight.
- Gravity depends on mass and distance
- It weakens with the square of distance
- It always attracts, never repels
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Gravitation?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Gravitation. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Gravitation in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Gravitation explains how the physical world behaves, from sport and transport to electricity and medicine.
Gravitation in detail
Newton's law of universal gravitation says that every mass attracts every other mass with a force proportional to the product of the masses and inversely proportional to the square of the distance between their centres: F = Gm₁m₂/r². G is the gravitational constant, 6.67 × 10⁻¹¹ N m²/kg².
Doubling the distance reduces the force to a quarter, an example of an inverse-square law. Gravity keeps planets in orbit, causes tides and gives us weight. Gravitational field strength at a planet's surface is g = GM/r², which depends on the planet's mass and radius.
How the interactive helps you understand Gravitation
Watch the orbit in the interactive. Use any sliders or buttons it offers to change the values and see how the orbit responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Gravitation.
Real-life uses and examples
- Use Gravitation to make sense of a practical and its results.
- Answer “explain” questions by linking Gravitation to a clear cause and effect.
- Predict what a ball, car or circuit will do with Gravitation before you do the calculation.
Common mistakes to avoid
- Mixing up Gravitation with a related quantity that has different units.
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Gravitation
What is Gravitation?
Gravity is the force of attraction between all masses, which holds planets in orbit and gives objects weight.
What are the most important points about Gravitation?
The main points are: Gravity depends on mass and distance; It weakens with the square of distance; It always attracts, never repels.
Why is Gravitation useful?
Understanding Gravitation explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Gravitation?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Gravitation?
Related topics in Physics include Temperature and Heat, Thermal Conduction, Gas Laws.