Give the location of the centre of mass of a
(i) sphere
(ii) cylinder
(iii) ring and
(iv) cube each of uniform mass density.
Does the centre of mass of a body necessarily lie inside the body?
(i) Centre of mass of a sphere lies at its geometrical centre.
(ii) Centre of mass of a cylinder lies at its geometrical centre i.e. at the mid-point of its axis of symmetry.
(iii) Centre of mass of a ring lies at its geometrical centre.
(iv) Centre of mass of a cube lies at its geometrical centre i.e. at the point of intersection of its diagonals.
No, it does not necessary that centre of mass of a body lie inside it, because in some cases such as a ring, a hollow cylinder, a hollow sphere and a hollow cube centre of mass lies outside.