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Homework Help: Electric Force

  1. Apr 7, 2008 #1
    1. The problem statement, all variables and given/known data
    Two identical conducting small spheres are placed with their centers 0.300m apart. One is given a charge of 12.0 nC and the other a charge of -18.0 nC. a) Find the electric force exerted by one sphere on the other. b) Next, the spheres are connected by a conducting wire. Find the electric force between the two after they have come to equilibrium.

    2. Relevant equations
    F_e = (k_e)*(q1*q2)/(r^2)

    3. The attempt at a solution
    k_e is a constant of 8.99e9 N*m^2/C^2
    plug the rest but I just don't understand the signs that well. Also when do i use the directional equation.
  2. jcsd
  3. Apr 8, 2008 #2
    For the signs, I suggest you think about what direction forces have depending on their charges instead of trying to to plug them into the equation.
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