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Homework Help: Electrostatic Force

  1. Mar 4, 2008 #1
    1. The problem statement, all variables and given/known data
    A metal sphere with a negative charge of 3.00x10^-6C is placed 12.0 cm from another similar metal sphere with a positive charge of 2.00x10^-6C. The two spheres momentarily touch, then return to their original positions. Calculate the electrostatic force acting on the two metal spheres.


    2. Relevant equations

    Fe=kq1q2/r^2

    3. The attempt at a solution

    Fe=(8.99x10^9)(3.00x10^-6)(2.00x10^-6)/(.12^2)
    Fe=3.75 N [Repulsive]

    For some reason the above formula wont work to get the answer that it says, am I doing something wrong?

    Answer should be 1.56x10^-1 N [Repulsive]
     
  2. jcsd
  3. Mar 4, 2008 #2
    what happends when the 2 charges touch? Charge is transferred, therefore you have to find out the final charge on eache sphere before you can use the formula.
     
  4. Mar 4, 2008 #3
    Oh yeah! Ok thanks I got it now!
     
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