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Homework Help: Point charges arranged as a trianngle

  1. Apr 23, 2009 #1
    1. The problem statement, all variables and given/known data
    Consider three charges at the vertices of an equilateral triangle of side a = 7 cm. qA = +2 µC, qB = +2 µC, and qC = -1 µC. (see attached picture)

    Find the x- and y- components of the electric force acting on qC

    2. Relevant equations
    i am doing everything right, but getting wrong answer ???

    3. The attempt at a solution
    x-comp cancel obviously, so im left with finding y-comp...

    F = kqAqC/r^2
    = 2.571e-1

    sin60(2.571e-1) = 2.2266e-1
    multiply by 2 = 4.453e-1 N (this is wrong though)

    i cant see the prob. The forces both point in positive y direction, so the y vectors sum
    please help, thanks!

    Attached Files:

  2. jcsd
  3. Apr 24, 2009 #2

    =9E9 x 2E-6 x 1E-6/0.07^2

    I see you are dividing by 7
    Two mistakes it's 7cm and then its r^2
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