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Homework Help: Quick Question

  1. Jan 22, 2007 #1
    The weight of a 0.7 kg object of charge Q is just balanced by another object of equal but opposite charge fixed to a support 132 cm above it. What is the magnitude of the charge Q (in μC)? [Note that 1 μC=1x10-6C.]

    Ok I know how to do this but it says I'm wrong... am I really wrong or is the computer wrong?

    .7kg times gravity = 6.86N

    The force between these two objects would be coulombs law.

    F= Ke (QQ/r^2) set force = to 6.86 and solve for Q

    It gave me .36443 micro C.

    What do you guys get?
  2. jcsd
  3. Jan 22, 2007 #2
    bump.. please just give me some guidance, I dont mean to impose im just in a crunch
  4. Jan 22, 2007 #3


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    Staff: Mentor

    1. It's not realistic to expect a response in less than a half hour.

    2. You still posted this in the wrong forum. :frown: We have a forum specifically for homework questions. This thread is going to be moved there, so don't worry about it, just remember to use that forum in the future for questions like this, OK? :smile:
    Last edited: Jan 23, 2007
  5. Jan 25, 2007 #4
    Anybody can help me solve this one. I was using the same method as post 1 but don't know if it is correct.
    Thanks in advance
  6. Jan 25, 2007 #5
    never mind found my own mistake and btw this is the correct way to solve this problem
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