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Homework Help: Kinetic Energy/Work Problem

  1. Oct 8, 2008 #1
    1. The problem statement, all variables and given/known data

    use the work energy theorem to find the force required to accelerate an electron (m=9.11 X10^-31 kg) from a speed of 1.50 X10^7 m/s in a distance of .0125

    2. Relevant equations
    W=Fd KE= 1/2mv^2

    W=KE


    3. The attempt at a solution

    I've tried this problem about eight times, and each time I managed to get a different answer, but this is my try at a solution

    W=Fx
    W/x= F

    W=1/2mv^2

    mv^2/2x = F

    however, this does not work for me.

    the answer is 3.56 X10 -19N
     
  2. jcsd
  3. Oct 8, 2008 #2
    To a speed of what? What is the unit of distance?
     
  4. Oct 9, 2008 #3
    Yeah, was this electron at rest to begin with, or was it in motion already? Check the wording of your question.
     
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