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Electric Forces need help

  1. Jan 12, 2008 #1
    Electric Forces...need help!!

    1. The problem statement, all variables and given/known data
    Two small plastic spheres each have a mass of 2.85 g and a charge of -39 nC. They are placed 3.06 cm apart (center to center).

    A. What is the magnitude of the electric force on each sphere?

    B. By what factor is the electric force on a sphere larger than its weight?

    2. Relevant equations

    3. The attempt at a solution
    A. K*q*q / r^2 = 0.0146 N
    B. I thought I could just do 0.0146 N / (0.00285kg * 9.81 m/s^2) = 0.523........is that right???
  2. jcsd
  3. Jan 12, 2008 #2

    Shooting Star

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    The concept is right.
  4. Jan 12, 2008 #3
    so what am I doing wrong??
  5. Jan 12, 2008 #4

    Shooting Star

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    Are you? What? I haven't checked the numbers.
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