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Homework Help: Rotation angle

  1. Sep 28, 2007 #1
    1. The problem statement, all variables and given/known data
    My book says that [tex] \epsilon \vec{n} \times \vec{q} [/tex] represents a small rotation about q.
    n is an normal vectors
    Obviously the cross product is orthogonal to both n and q, but I did not know it corresponded to an angle?
    BY the way, how do you make a cross product in tex?
    2. Relevant equations

    3. The attempt at a solution
    Last edited: Sep 28, 2007
  2. jcsd
  3. Sep 28, 2007 #2


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    Homework Helper

    cross product in tex? \times will be fine

    the epsilon correspond to the small amplitude of your infinitestimal rotation I think
  4. Sep 28, 2007 #3
    But why does this represents an angle?
  5. Sep 28, 2007 #4


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    It doesn't represent an angle. It represents an infinitesimal displacement. A small displacement from a vector q rotated around an axis along n should be perpendicular to both. Hence nxq.
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