Question

Three particles of mass m each are placed at the three corners of an equilateral triangle of side a. Find the work wihch should be done on this system to increase th esides of the triangle to 2a.

Answer 1

Initially, the side of the triangle = a
to increase it to 2a
$workdone=\frac{G{M}^2}{2a}+\frac{G{M}^2}{a}=\frac{3G{M}^2}{2a}$