Gravitational potential energy of a system

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Homework Help Overview

The discussion revolves around calculating the gravitational potential energy of a system consisting of eight 10 kg masses positioned at the corners of a cube with a side length of 0.25 meters. Participants are exploring the implications of the gravitational potential energy equation and the methodology for summing the contributions from each mass pair.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • One participant describes an attempt to calculate the potential energy by considering each pair of masses individually. Others suggest a different approach by considering the work required to remove each mass to infinity, prompting questions about the implications of the number of masses involved.

Discussion Status

The discussion is active, with participants questioning the initial approach and exploring alternative methods. Some guidance has been offered regarding the process of calculating work for each mass, while others express concerns about the practicality of this method. There is recognition of the need to account for all masses in the system.

Contextual Notes

Participants note the complexity of calculating potential energy for multiple masses and express a desire for a more efficient method. The original poster's approach and the subsequent suggestions highlight the challenges of the problem setup.

roshan2004
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Homework Statement


What is the gravitational potential energy of a system of 8 masses of 10 kg each placed at the corners of a cube of length 0.25 meter apart.



Homework Equations


U=-G*m1*m2/r


The Attempt at a Solution


I have actually taken one particle pair at a time and sum all of their potential energy, but the answer is not quite right.
 

Attachments

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You just want to find the work needed to remove all the masses to infinity.
So pick one ... remove it: how much work would that take?

OK so now you have 5 masses - pick one, remove it: how much work did that take?

Rinse and repeat.
 
I think there are 8 masses in here.
 
Good - you are paying attention ;)
How would you have to change the suggestion to account for the different number of masses?
 
I think it will be very tiresome to pick each and every particle and work out their work done in bringing them from infinity to that position. There must be some quick method...
 
Yes and no - there is no getting around having to do this for every particle.
But you only have 8 steps to do, and, once you get started, you should notice a pattern that makes things easier.

Finding this out is a big part of why the exercize is set in the first place.
There is no Royal road to knowledge.
 

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