I know the definition of radius of gyration. But don't know what does it mean? What are the importance of it? Is it similiar to centre of mass? I want to clear my problem. Let you know only the definition of centre of mass. But you don't know why this term is important. If I tell you that, if we apply force along to the centre of mass, it seems that that the force has workes through its whole body. But only definition was not sufficient to realize it better. At the same way, I want to learn more about radius of gyration.