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Homework Help: Transformation of Angles (Relativity)

  1. May 15, 2012 #1
    1. The problem statement, all variables and given/known data
    Find and compare the transformations of the angle of the velocity vector of a particle and the angle of an inclined stick. The relationship between the two frames is as usual.

    In frame S' a stick makes an angle of θ' with the x' axis. What is the angle θ measured in the S frame? What is the length in the S frame?

    2. Relevant equations

    x' = xcosθ + ysinθ
    y' = -xsinθ + ycosθ ?

    3. The attempt at a solution

    I really have no idea what the question is really asking. Thanks.
  2. jcsd
  3. May 15, 2012 #2


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    Hi Phyrrus! :smile:
    When an observer measures the direction of a line (such as this stick), he does so at a constant time in his frame.

    (you can think of a line as a point travelling at infinite speed in the observer's frame! :biggrin:)

    A constant time in his frame is not a constant time in the new frame. :wink:
  4. May 19, 2012 #3
    thanks mate
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