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Homework Help: Magnetic Fields & Cross Products

  1. Apr 2, 2005 #1
    I desperately need help, for I am quite lost on this question:

    Consider the example of a positive charge moving in the xy plane with velocity v = cos(theta)x + sin(theta)y (i.e., at angle theta with respect to the x axis). If the local magnetic field is in the +z direction, what is the direction of the magnetic force acting on the particle?

    Express the direction of the force in terms of theta, as a linear combination of unit vectors, x, y, and z.

    F = qBV

    One hint given was to find the determinant expression for the cross product, but I don't know what this means.

    Thanks for any replies.
  2. jcsd
  3. Apr 2, 2005 #2


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    [tex] \vec{F}_{Lorentz}=q \vec{v}\times\vec{B} [/tex]

    Do you know to compute a cross product...?Through what methods...?

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