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Homework Help: Electric field of two charges

  1. Jan 20, 2009 #1
    1. The problem statement, all variables and given/known data
    In the figure below , what is the electric field at point P?

    2. Relevant equations

    F = k*(q1*q2)/r^2

    3. The attempt at a solution

    F = k*(2q^2) / (2d + d)^2

    That is my attempt, but it's not a possible answer.. Any help is appreciated.
  2. jcsd
  3. Jan 20, 2009 #2


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    At P the fields are in the opposite direction. So find the field at P due to q and 2q, and take the difference.
  4. Jan 20, 2009 #3
    Oh ok, so it should be kq/2d^2 then?
  5. Jan 20, 2009 #4


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