Gravitaional Potential Energy help, please

AI Thread Summary
The discussion revolves around calculating the gravitational potential energy of a system of three spheres after one is removed. The user initially used the formula U=-G(m1m2/r12 + m1m3/r13 + ...) to compute the potential energy but received an incorrect result. After reviewing their calculations, they identified a small error that led to the wrong answer. The user ultimately resolved the issue on their own. The thread highlights the importance of careful calculation in physics problems.
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Homework Statement


Four uniform spheres, with masses mA = 350 kg, mB = 600 kg, mC = 1500 kg, and mD = 300 kg, have (x, y) coordinates of (0, 50 cm), (0, 0), (-80 cm, 0), and (40 cm, 0), respectively. Sphere A is then removed.
(a) Calculate the gravitational potential energy of the remaining three-particle system.



Homework Equations


U=-Gm1m2/r12-Gm1m3/r13-...


The Attempt at a Solution


U=-G(McMd/Rcd+McMb/Rcb+MbMd/Rbd)
U=-G(1500*300/.12+1500*600/.8+600*300/.4)=-3.55e-4 J
It's telling me this is wrong but I can't see where I'm going wrong. Thanks in advance.
 
Last edited:
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Nevermind. I found my small error. Thanks, anyway.
 

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