# Cube with equal charges at all vertices

1. May 19, 2012

### mateomy

If I have a cube with a charge q at each corner, but the problem doesn't say anything about the cube being grounded. Can I assume that the total potential energy will be a linear combination of the individual six sides?

2. May 20, 2012

### tiny-tim

hi mateomy!
(i don't understand where the sides come into it )

the total potential energy at a particular point is always the sum of the individual potential energies at that point

3. May 20, 2012

### SammyS

Staff Emeritus
The electric potential depends upon the point at which it's being calculated.

The total potential energy of the system depends upon the quantity of charge, q, and the size of the cube, usually specified by the length of any edge.

You can find the total potential energy of this system of charges by finding the total work done to "build" this system from scratch.

How much work is required to bring the first charge into position --- with none of the others present?

How much work is required to bring a second charge into position ?

... etc.