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Electron held up against force of gravity

  1. Mar 12, 2009 #1
    1. The problem statement, all variables and given/known data

    an electron is held up against the force of gravity by the attraction of a fixed proton some distance above it. How far above the electron is the proton?

    2. Relevant equations

    F= ((K)(Q1)(Q2))/R^2

    Qe = 1.6x10^-19

    3. The attempt at a solution

    Using the formula for Coulombs Law I used the K constant of 9x10^9 and Qe for Q1 and Q2. This is all divided by R^2 (I'm solving for R). The problem is I don't know if there is a gravitational constant for Force or what I'm missing. What's the next step?
     
  2. jcsd
  3. Mar 13, 2009 #2

    rl.bhat

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    Homework Helper

    Write F = mg where m is the mass of the electron.
     
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