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Homework Help: Magnetic force problem

  1. Oct 27, 2005 #1
    When a charged particle moves at an angle of 19° with respect to a magnetic field, it experiences a magnetic force of magnitude F. At what angle (less than 90°) with respect to this field will this particle, moving at the same speed, experience a magnetic force of magnitude 1.8F?

    can someone please tell me why doing a simple 19/f=x/1.8f cross-multiply and divide won't work????

    it's my last problem on this dang homework!:grumpy:
  2. jcsd
  3. Oct 28, 2005 #2


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    Why should it work? You have no basis for writing that proportion.

    You need use the Lorentz force equation for charged particles moving in a magnetic field. Does this look familiar: [itex]\vec F = q \vec v \times \vec B[/itex]? Given [itex]\vec v[/itex] and [itex]\vec B[/itex] could you determine the magnitude of [itex]\vec F[/itex]? How does it relate to the angle between the vectors?
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