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Homework Help: Kinetic Energy among a set of Point Charges

  1. Feb 15, 2010 #1
    1. The problem statement, all variables and given/known data

    A set of point charges is held in place at the vertices of an
    equilateral triangle of side 10.0 cm, as shown in the figure (a) .
    Find the maximum amount of total kinetic energy that will be
    produced when the charges are released from rest in the
    frictionless void of outer space.


    2. Relevant equations

    Unsure, but believe this one is paramount:

    V = k*(q/r)

    3. The attempt at a solution

    I'm using the formula V = k(q1)/r1 and the example in my textbook on page 590,
    which is for only 2 point charges within an isosceles triangle, simply adds the
    V1 + V2 to get Vtotal, so I assumed (probably incorrectly) that I could use
    this method with 3 charges within an equilateral triangle and simply added the
    V1 + V2 + V3 = 809.1 N*m/C. However, they want the answer in joules,
    so what if I was even correct in my method, what should be done to my
    answer in order to convert it to joules? Are N*m/C = Volts? Wouldn't that
    mean I would need to then multiply by the same charges I just multiplied by?
    And would I use each individual charge added together, or... what do I do with
    these Coulombs?
  2. jcsd
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