Question

Two identical copper spheres of radius R are in contact with each other. If the gravitational attraction between them is F, find the relation between F and R.

Answer 1

Instead of two big spheres of radius $R$ assume . $2$ small sphere of mass $m$ at their respective COM.

then $F=\frac{Gm\times m}{{\left(2R\right)}^2}F=\frac{G{m}^2}{4R^2}$