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Homework Help: Magnitude of net electric field

  1. Jul 17, 2005 #1
    Four point charges have the same magnitude of 2.2 10-12 C and are fixed to the corners of a square that is 3.0 cm on a side. Three of the charges are positive and one is negative. Determine the magnitude of the net electric field that exists at the center of the square.

    i tried using E=(k|q|)/r^2 but it wasn't working and i'm not sure how to combine the electric fields for all of the outside charges...

    -annie
     
  2. jcsd
  3. Jul 17, 2005 #2
    Why doesn't that formula work?
     
  4. Jul 17, 2005 #3
    this is what i tried ((8.99e9)(2.2e-12))/((3.0e-2)^2) and i got 21.976... so now am i supposed to multiply by 4??? cause that answer i got isn't right
    -annie
     
    Last edited: Jul 17, 2005
  5. Jul 17, 2005 #4
    ahha i figured it out... :)
     
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