(N/A) The centre of mass is a point where the entire mass of the body is assumed to be concentrated. It is independent of the gravitational field.
The centre of gravity is a point where the entire weight of the body is assumed to act. It depends on the gravitational field.
Key differences:
$1$. Centre of mass is defined for any system of particles,regardless of the presence of gravity. Centre of gravity is defined only in a gravitational field.
$2$. In a uniform gravitational field,the centre of mass and the centre of gravity coincide.
$3$. For a large body in a non-uniform gravitational field,the centre of gravity may differ from the centre of mass.
Experimental determination of the centre of gravity:
As shown in the figure,an irregular body is suspended from different points $(A, B, C)$. The vertical line passing through the suspension point and the body is drawn. The intersection of these vertical lines $(AA_1, BB_1, CC_1)$ gives the centre of gravity $(G)$.