Question

The gravitational potential energy of an isolated system of three particles, each of mass $m$, at the three corners of an equilateral of side $l$ is

• A. $-\frac{Gm^2}{l}$
• B. $-\frac{Gm^2}{2l}$
• C. $-\frac{2Gm^2}{l}$
• D. $-\frac{3Gm^2}{l}$

Answer 1

Answer: (D)

Gravitational potential energy of a pair of particles
$ = -\frac{Gm^2}{l}$
Since we have three pairs, therefore the total
gravitational potential energy is $- \frac{3Gm^2}{l}$