Changes in gravitional potential energy HELP!?

The figure below (a square with four sides of length d. The four particles decribed are the corners of the square) shows four particles, each of mass 40.0 g, that form a square with an edge length of d = 0.750 m. If d is reduced to 0.250 m, what is the change in the gravitational potential energy of the... show more The figure below (a square with four sides of length d. The four particles decribed are the corners of the square) shows four particles, each of mass 40.0 g, that form a square with an edge length of d = 0.750 m. If d is reduced to 0.250 m, what is the change in the gravitational potential energy of the four-particle system?
2 answers 2