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Homework Help: Direction of force using right hand rule

  1. Oct 15, 2007 #1
    1. The problem statement, all variables and given/known data

    http://img206.imageshack.us/img206/5084/71282075fy0.jpg [Broken]

    2. Relevant equations

    There are many variations on the right hand rule, but I'm most confortable with the following. Current is in the direction of thumb, B field is in direction of fingers and F shoots out of the palm

    3. The attempt at a solution

    I can find the magnitude easily using F=BiLsin(theta). I get 3N. Can someone just confirm that theta is the angle between B and i? I'm not sure how to find the direction with the right hand rule in such a case (where there is an angle between B and I). For reference, the answer is into the page.
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Oct 15, 2007 #2


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    Sounds good to me
    This right-hand rule tells you the direction of the magnetic field created by the wire, not the direction of the force on the wire. See this page <http://www.molecularexpressions.com/electromag/electricity/generators/index.html> [Broken] for more information. The rule you need is in figure 9.
    Last edited by a moderator: May 3, 2017
  4. Oct 15, 2007 #3
    left hand rule? never heard of such a thing!
    Are you aware of any other methods to find direction of force using right hand rules?
  5. Oct 15, 2007 #4

    Doc Al

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    Here are two links that may help with the right hand rule:
    http://www.physics.brocku.ca/faculty/sternin/120/slides/rh-rule.html [Broken]
    http://physics.syr.edu/courses/video/RightHandRule/ [Broken]

    I always use the version that's shown (in the first link) in the right most middle diagram--where the fingers curl from one vector to the other and the thumb gives you the force. The second link shows videos of someone actually using it in every possible case!
    Last edited by a moderator: May 3, 2017
  6. Oct 15, 2007 #5


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    Homework Helper

    Go ahead and use the right hand rule that you wrote... you should get your palm facing into the page...
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