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Homework Help: Cross Product Directions

  1. Oct 19, 2007 #1
    1. The problem statement, all variables and given/known data

    Sketch a 3-dimensional picture showing the horizontal plane, a point P on the plane, a vertical line through P, and three vectors at P: vector A points vertically upward; vector B points toward the east; vector C points toward the south.

    Now determine the cross product directions.
    A x C
    A x B
    B x C
    B x A

    You have choices of: up, down, north, south, east, and west.

    2. Relevant equations

    ??

    3. The attempt at a solution

    I don't know how to attempt to solve this. Someone please help.
     
  2. jcsd
  3. Oct 19, 2007 #2
    Have you learned the right hand rule?
     
  4. Oct 21, 2007 #3
    As I said, I have no idea on how to solve this problem.

    I know the right hand rule, but I thought that it was only for currents, directions of B fields, and the direction of the magnetic force.

    Someone please help if you can.
     
  5. Oct 21, 2007 #4
    The right hand rule also applies to the cross product of vectors.

    http://mathworld.wolfram.com/Right-HandRule.html

    "The right-hand rule states that the orientation of the vectors' cross product is determined by placing u and v tail-to-tail, flattening the right hand, extending it in the direction of u , and then curling the fingers in the direction that the angle v makes with u . The thumb then points in the direction of u x v."
     
  6. Oct 21, 2007 #5
    Thanks man. I was using my left hand.... :blushing:
     
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