Centre of Mass

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Centre of Mass

Although the mass of an object is spread out across its body, it is possible to find a single point where all of the mass appears to be. This point is called the object’s centre of mass.

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All in a single point

  • The centre of mass is the point through which an object’s weight appears to act.
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Hanging objects

  • If an object is hung from a string, it will hang with its centre of mass directly below the point that it is hung from.
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Toppling over

  • An object will fall over if its centre of mass is outside its base.
  • An object will fall off a surface if its centre of mass isn’t over the surface.
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Uniform solid

  • The centre of mass of a uniform, regular solid will be at its centre.
  • We know this by symmetry.

Centre of Mass - Example

The dog remains upright because he keeps his centre of mass over his legs.

Jump to other topics

1Measurements & Errors

2Particles & Radiation


4Mechanics & Materials


6Further Mechanics & Thermal Physics (A2 only)

7Fields & Their Consequences (A2 only)

8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

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