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Homework Help: Magnitude and direction of the net force on charge -3Q and charge 4Q

  1. May 13, 2010 #1
    1. The problem statement, all variables and given/known data

    Four charges are located at the corners of a square as shown below. Calculate the magnitude and direction of the net force on charge -3Q and charge 4Q.

    (sorry don't have picture, but it is of a square with corners -Q, 2Q, -3Q, and 4Q clockwise).

    2. Relevant equations

    F= K(q1)(q2)/r^2

    K= 8.99x10^9

    3. The attempt at a solution

    I don't understand how to start with the information I've been given, it seems like its not enough.
  2. jcsd
  3. May 14, 2010 #2


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    Science Advisor
    Homework Helper

    Hi balletgirl! :wink:

    Start with the charge of -3Q.

    Draw the three vectors through it representing the forces from the other three charges.

    Then add those three vectors by adding their components …

    what do you get? :smile:
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