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Homework Help: Movement of Charged Particles in a field

  1. Jan 27, 2007 #1
    1. The problem statement, all variables and given/known data
    Two electrons are 10-9m Apart when they are released.What is their speed when they are 10-8m apart?



    2. Relevant equations
    Ek=-EE
    EE=Kq1q2
    -------
    r


    3. The attempt at a solution
    Ive tried 1/2mv^=-(Ke(squared) - Ke(squared)
    ------------ -----------
    r2 r1
    And i dont seem to get the answer
    By the way the answer to the question is 4.78x10^5 m/s
    thanks for the help
     
  2. jcsd
  3. Jan 28, 2007 #2
    Calculate electric potential energy when they are 10^-9m apart, and then when they are 10^-8m apart. The change in energy has become kinetic energy, and you may calculate it from this.
     
  4. Jan 28, 2007 #3
    I did that.. And i still get the wrong answer but its pretty close.. i guess its a calculation error.. i will go back and recheck thanks for the help...
     
  5. Jan 28, 2007 #4
    Yeah doublecheck your calculation. I did it and I got something like 4.79e5, so I'm pretty sure that's how you do it.
     
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