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Two Electrons and Distance Equation

  1. Jan 18, 2012 #1
    An electron (mass of 9.110×10-31kg and charge of -1.602×10-19C) is released at rest above the surface of the earth (where g = 9.81 m/s2). A second electron directly below it exerts an electrostatic force on the first electron that exactly cancels the gravitational force. What is the distance between the two?

    2. Relevant equations
    F=Eq
    F=ma
    F=kq1q2/r^2

    3. The attempt at a solution
    I honestly don't know at all how to solve this. If someone could explain to me how and maybe show me the initial steps, that would be great!!
     
  2. jcsd
  3. Jan 18, 2012 #2

    Delphi51

    User Avatar
    Homework Helper

    We aren't supposed to help before you make an attempt.
    But I can give you a little hint. Just write the obvious:
    force of gravity = electric force
    Then look for the formula for each side of the equation and write the next step in formulas. Solve for the quantity you want to find. Put in the numbers and run it through your calculator.
     
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