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Homework Help: Electron speed

  1. Feb 28, 2009 #1
    1. The problem statement, all variables and given/known data

    An electron moves with speed 9.50 105 m/s in a uniform magnetic field of 4.4 T, pointing south. At one instant, the electron experiences an upward magnetic force of 3.40 10-14 N. In what possible directions might the electron be moving at that instant? Give your answers as angles clockwise from south (from 0° to 360°), in increasing degrees.

    2. Relevant equations

    F=qB(vsin theta)

    3. The attempt at a solution
    I keep trying to plug all the knowns into this equation but i cannot seem to find the right answer.
    3.4e-14=(1.6e-19)(4.4)(9.5e5sin theta) and find inverse.

    the 2 answers should be clockwise from south
  2. jcsd
  3. Mar 1, 2009 #2


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    Hi phy112! :smile:

    (have a theta: θ :wink:)
    just solve for sinθ … should give you two answers :smile:
  4. Mar 1, 2009 #3
    i did that and got an angle of 2.91. that isnt right though. i am wondering if there is another step im missing.
  5. Mar 1, 2009 #4


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    You should have got two angles.
  6. Mar 1, 2009 #5
    arent the two angles the same??
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