The centre of gravity of an object (sometimes called the centre of mass) is defined as:

The point through which the weight of an object acts

For a symmetrical object of uniform density, the centre of gravity is located at the point of symmetry

For example, the centre of gravity of a sphere is at the centre

The centre of gravity of a regular shape can be found by symmetry

The centre of gravity of an irregular object can be found by locating its balance point

A broomstick has a centre of gravity slightly closer to the head of the broom since there is more mass located there