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Charged particle and Earth's magnetic field at equator question

  1. Feb 17, 2009 #1
    1. The problem statement, all variables and given/known data

    Stumped on this one.
    A charged particle hurles through space creatings its own magnetic field, if it strikes the Earth's equator, the 2 magnetic fields interact and...

    a) do not affect the particles direction
    b) change the particles speed but not direction
    c) change the particles speed and direction
    d) change the particles direction
    e) bounce it back in the direction it came from.

    3. The attempt at a solution

    I chose b but this is wrong. so I am thinking it's c...
  2. jcsd
  3. Feb 17, 2009 #2


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  4. Feb 17, 2009 #3
    Thank you for replying I appreciate it.

    Ok from your link after reviewing I would say.....

    d) change the particles direction

    but I don't see how this also wouldn't affect speed as well.
  5. Feb 17, 2009 #4


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    I'd say that shows some understanding.

    Good luck.
  6. Feb 17, 2009 #5
    Yeah I am trying to understand it, alot of this seems a little advanced for 9th grade science. Definitely not my best class.

    I am going with c then, I think the fact that it was the equator confused me a little bit as far as direction goes.
  7. Feb 17, 2009 #6


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    This would be my thinking.

    The force of the B field is the vector cross product of the field and the particle's velocity. The idea of it being at the equator is to suggest that the B field is ⊥ to its radial direction from the sun. So with B ⊥ V and hence the F ⊥ V (the vector cross product does that), I would say that the force acts to deflect the particle. Since the Force is ⊥ to the direction of motion it isn't doing any work on the particle and hence its kinetic energy remains the same.
  8. Feb 18, 2009 #7
    Ok since the kinetic energy would be the same then i was right earlier with just the direction only being changed? using the right hand rule
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