Question

what is centre of gravity​

Answer 1

In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity. This is a very good approximation for smaller bodies near the surface of Earth, so there is no practical need to distinguish "center of gravity" from "center of mass" in most applications, such as engineering and medicine.

Answer 2

a point from which a weight of a body may be considered to act uniform gravity it is the same as the centre of mass