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Homework Help: E Field stationary observer.

  1. Apr 26, 2006 #1
    I have a problem that I can not understand what I am doing wrong.

    A rocket moves at 1.0*18^6 m/s. Inside is an E Field (coming out of the page of the book) that is 2.0*10^6 V/m. There is also a B Field in the rocket pointing up that is -1.0 T. What is the E Field observed by someone on Earth. (The rocket is sooming past Earth.)

    I used E = E - V X B

    = E - V*B (V and B are perpindicular)

    = sqrt((1.0*10^6)^2 + (2.0*10^6)^2)

    However this does not yield the correct answer. Any help is appreciated.
    If anyone is working the numbers I got 2.24*10^6.
  2. jcsd
  3. Apr 27, 2006 #2
    a hint,

    the v in the Lorentzformula that you used, does not correspond to the velocity of the rocket. This v is the velocity of the charge that moves in the E/B field. Also, the given rocket velocity is with respect to the earth, right ?


    The magnitude of the E and B field are given with respect to what base exactly ? You need to know this if you wanna (which you are gonna) apply the Lorentz transformations.

    What is the orbit of the rocket with respect to the earth ?

    You see, there are some aspects missing in your question.

    Last edited: Apr 27, 2006
  4. Apr 27, 2006 #3


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