Q.For which of the following objects will the centre of mass NOT be at their geometrical centre? (I) An egg (II) A cylindrical box full of rice (III) A cubical box containing assorted sweets (A) Only (I) (B) Only (I) and (II) (C) Only (III) (D) All, (I), (II) and (III).

[!TLDR] An egg's mass is not distributed with full geometric symmetry (yolk is off-centre and shells vary in thickness), so its centre of mass is not exactly at its geometric centre; a uniformly-filled cylinder or cub …

A cylindrical box FULL of rice, and a cubical box containing many small, roughly-uniformly-distributed sweets, are both good approximations to uniform-density objects with full geometric symmetry, so by the rule 'a symmetric object of uniform density has its c.m. at the geometric centre' (4.13.4, points 5-6), their centres of mass are at their geometric centres. An egg, however, is NOT uniform: it has a denser yolk generally positioned off-centre within the white, and a shell of non- …

Apply the c.m.-at-geometric-centre rule only to objects that are genuinely uniform in density and shape-symmetric; identify w …

Assuming any 'container full of small items' is automatically non-uniform -- a box packed with many small, similar items distributed evenly approximates a uniform con …