Physics - 8 Forces in Balance - 8.6 Centre of Mass

Centre of mass

the point at which the mass of an object can be thought to be concentrated

Suspended equilibrium

A state after when an object is released and comes to rest with its centre of mass below the point of suspension.

Freely suspended

If a suspended object returns to its equilibrium position after the turning force is taken away

Where is the centre of mass for a symmetrical object?

the intersection of the axis of symmetry

How to find the centre of mass?

1. Make a small hole in the object and hang it up so that it is free to swing without obstruction.

2. Hang a plumb line (a piece of string with a weight hanging from it) from the same suspension point. This lets you mark the vertical line directly below the suspension point.

3. Drill another hole at a different location within the object.

4. Again hang a plumb line to determine the vertical and mark it on.

5. The point at which the two marked lines cross is the centre of mass.