Question

Define Centre of mass with significance ?

Answer 1

A point, near, or within a body at which the object's mass can be assumed to be concentrated, it coincides with the centroid for a body of uniform density, and with the centre of gravity in a uniform gravitational field.. centre of mass synonyms: centre of gravity,centre of inertia. Centre of mass 

Answer 2

Centre of mass : The centre of mass of a system of particles is the point at which whole of mass of system assume to be concentrated .
Significance : It is easy to deal motion , momentum and energy of a system of particles using concept of centre of masss rather than the individual particles .