Centre of Mass and Stability
The centre of mass is the point where an object's weight appears to act, and low centres with wide bases give greater stability.
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The centre of mass is the point where an object's weight appears to act, and low centres with wide bases give greater stability.
- A wide base improves stability
- An object topples if its centre of mass moves outside the base
- Racing cars are built low
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Centre of Mass and Stability?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Centre of Mass and Stability. 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 Centre of Mass and Stability in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Centre of Mass and Stability explains how the physical world behaves, from sport and transport to electricity and medicine.
Centre of Mass and Stability in detail
The centre of mass is the point where an object's weight can be considered to act. For a uniform symmetrical object it lies at the geometric centre. You can find it for a flat irregular shape by hanging it from different points and marking plumb lines.
An object is stable if a vertical line through its centre of mass falls inside its base when tilted. A low centre of mass and a wide base increase stability, which is why racing cars are low and wide while a tall bus can topple more easily. Stability matters in vehicle design, buildings and ladders.
How the interactive helps you understand Centre of Mass and Stability
Watch the lever in the interactive. Use any sliders or buttons it offers to change the values and see how the lever 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 Centre of Mass and Stability.
Real-life uses and examples
- Use Centre of Mass and Stability to make sense of a practical and its results.
- Answer “explain” questions by linking Centre of Mass and Stability to a clear cause and effect.
- Predict what a ball, car or circuit will do with Centre of Mass and Stability before you do the calculation.
Common mistakes to avoid
- Mixing up Centre of Mass and Stability 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 Centre of Mass and Stability
What is Centre of Mass and Stability?
The centre of mass is the point where an object's weight appears to act, and low centres with wide bases give greater stability.
What are the most important points about Centre of Mass and Stability?
The main points are: A wide base improves stability; An object topples if its centre of mass moves outside the base; Racing cars are built low.
Why is Centre of Mass and Stability useful?
Understanding Centre of Mass and Stability explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Centre of Mass and Stability?
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 Centre of Mass and Stability?
Related topics in Physics include Pressure in Liquids, Work Done, Conservation of Energy.