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Homework Help: Lorentz Vector Subtraction

  1. Oct 16, 2011 #1
    1. The problem statement, all variables and given/known data

    A projectile is fired from a canon at a velocity of 0.4c at an elevation angle of 30° to the X-axis. An observor is moving at a velocity of 0.1c relative to the canon along the X direction.
    (a) At what angle does the observor measure the projectile to be fired?
    (b) What is the projectile’s speed relative to the observor?

    2. Relevant equations

    3. The attempt at a solution

    Am I correct in thinking that I use the same method of Lorentz vector subtraction as shown near the bottom of the linked-to webpage below?


    i.e. the section entitled, "What, therefore, would r & θ appear to be to an observor in relatively moving S'?"

    Example 1

    Or does anyone suggest another (simpler?) method?

    Thank you.
    Last edited: Oct 16, 2011
  2. jcsd
  3. Oct 16, 2011 #2
    Sorry, hadn't added in the linked-to webpage, which I've just done!
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