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Homework Help: A Rectangle Parallel to a Magnetic Field

  1. Jul 19, 2011 #1
    1. The problem statement, all variables and given/known data

    file:///Users/LabGuest/Desktop/CH26.tiff

    2. Relevant equations

    FB= qv cross B

    3. The attempt at a solution


    If the the rectangle is parallel to the magnetic field and we know that FB is perpendicular to the B field itself than there should be a net Torque but no net force. Is this assumption correct?

    My first intuition was to say there was a net force and no net torque but I think that is wrong because magnetic force acts perpendicular to the magnetic field (B).
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     

    Attached Files:

    • CH26.gif
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  3. Jul 20, 2011 #2

    ehild

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    Yes, it is correct. Can you explain, why?

    ehild
     
  4. Jul 20, 2011 #3
    Yes because Magnetic Force = qv cross B thus it acts perpendicular to the magnetic field (B) since it is a cross product. The magnitude of the force is qvbsin(theta).
     
  5. Jul 20, 2011 #4

    ehild

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    Homework Helper

    But then there can be a net force on the rectangle, perpendicular to it, is it right?

    What is v in the formula?

    ehild
     
    Last edited: Jul 20, 2011
  6. Jul 20, 2011 #5
    there is a different formula (derived from the formula u wrote) used in case of currents ... do you know it?
     
  7. Jul 20, 2011 #6
    I would consider the magnetic force on each segment of the loop and sum these.
     
  8. Jul 20, 2011 #7
    correct way !!! :approve:
     
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