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Length contraction

  1. Jun 24, 2011 #1
    As I understand it, there is no length contraction in the direction perpendicular to the motion being described. So if I were to observe a circle moving along a line (not rostating) and I were to measure the radius in te direction parallel to the motion, I would observe a contracted radius, and therefore calculate a smaller circumference. But if I were to measure the radius in the direction perpendicular to motion, I would observe the inertial radius and therefore the inertial circumference. Does this mean that to calculate the circumference of a moving circle, I would need to treat it as an ellipse?
  2. jcsd
  3. Jun 24, 2011 #2


    Staff: Mentor

    Yes, that is correct.
  4. Jun 24, 2011 #3


    User Avatar
    Gold Member

    A spherical object will compress along its axis of travel into a disclike shape (an oblate spheroid).
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