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Homework Help: Motional EMF (direction of moving bar)

  1. Oct 13, 2011 #1
    1. The problem statement, all variables and given/known data

    Can someone please explain to me how to determine the direction of the veloicty of a bar that is conducting and inducing a current.

    Fb=q(VxB)???
     
  2. jcsd
  3. Oct 13, 2011 #2
    Use F = IL x B instead.
     
  4. Oct 13, 2011 #3
    Consider a conducting wire attached to a small weight. Fg acts to the right, and Fb (due to magnetic field perpendicular) is directed to the left. Say Fb>Fg. If the system is allowed to reach "steady state" why is the motional emf not Fb-Fg and directed to the right?
     
  5. Oct 13, 2011 #4
    The only reason I am asking is that I read that the magnetic force that develops due to a velocity always has to oppose it... Which doesnt seem like it would always be the case. Especially if there is a current passing through the wire such that it is that force giving it the acceleration.
     
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