PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Four identical point masses, each of mass m, are fixed at the four corners of a square of side a lying in the same plane.
(i) List all the unique pairs of masses in the system and write an expression for the gravitational potential energy associated with each pair in terms of G, m, and the distance between the pair.
(ii) Hence obtain an expression for the total gravitational potential energy of the system in the form Utotal=−aGm2(α), and determine the numerical value of α.
(iii) Comment on what this total negative energy signifies about the binding of the four–mass configuration.