Potential Energy of a Three-Particle System

AI Thread Summary
The discussion centers on calculating the gravitational potential energy of a three-particle system after removing one sphere. The user initially applies the formula for gravitational potential energy but struggles to arrive at the correct answer. Key points include the need to convert centimeters to meters for accurate calculations and the importance of considering the direction of the forces involved. The user expresses confusion about whether the removal of sphere A affects the calculations and acknowledges a potential oversight in unit conversion. Accurate unit conversion and proper application of the gravitational potential energy formula are crucial for solving the problem correctly.
sizzler
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I am working on this problem:

Four uniform spheres, with masses mA = 200 kg, mB = 100 kg, mC = 1900 kg, and mD = 250 kg, have (x, y) coordinates of (0, 50 cm), (0, 0), (-80 cm, 0), and (40 cm, 0), respectively. Sphere A is then removed. Calculate the gravitational potential energy of the remaining three-particle system

And I do not understand why I cannot get the correct answer. Potential energy equals...

= -G(m1m2)/r

Or in my case...
= -G(100*1900/80 + 100*250/40 + 1900*250/120)
= -4.6433E-7 J

Do I need to account for the loss of sphere A? Or is my error not accounting for the opposite direction of sphere C? Thanks for any advice.
 
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Hm..did you convert cm's into m's?
 
Wow, I can't believe I'm that dumb. Thanks! :)
 

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