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Homework Help: Two polystyrene balls, one has a charge twice the amount than the otherfind charges

  1. Jan 25, 2012 #1
    1. The problem statement, all variables and given/known data
    Two balls of polystyrene foam are about 4 cm from each other and repel with an electric force of 0.2 N. Find the values of the two charges knowing that one of the balls has a charge that is twice the other.

    2. Relevant equations
    F= (kq1q2)/r2

    3. The attempt at a solution
    F= (k·Q·2Q)/r2
    0,2 = ( 9x109·2Q2 ) / (0,04)2

    Q= +1,77 x 10-14

    AND its wrong! The right answers should be :
    (+or-)188nC, (+or-)267nC
    Last edited: Jan 25, 2012
  2. jcsd
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