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Homework Help: Electric Potential of charges on a rectangle

  1. Apr 9, 2010 #1
    1. The problem statement, all variables and given/known data

    Consider charges placed at the corners of a rectangle. This rectangle is a horizontal rectangle and is .43 m long and .25 m wide. At the upper right corner there is a charge of 7.0 µC. At the bottom right there is a charge of -14 µC. At the bottom left there is a charge of -8.0 µC. At the upper left there is Point P.
    Find the electric potential at point P due to the grouping of charges at the other corners of the rectangle.
    Answer in units of V.

    2. Relevant equations
    These may help:
    EP = -qE(omega)d
    PE=kq/r

    3. The attempt at a solution

    I worked the Potential Energy (so I thought) for point P and drew it out. Then I added the results vectorily, yet, I still got it wrong 5 times. If you could help that'd be awesome.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 10, 2010 #2

    kuruman

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    Science Advisor
    Homework Helper
    Gold Member

    Potential energy is a scalar, not a vector. There is nothing to "draw out". You should just add the kq/r terms for each charge because all that matters is the distance to point P not the direction.
     
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