Physlet Illustration: Relativistic Length Contraction

 

 

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Red stick's frame of reference Green stick's frame of reference
In this simulation, two meter sticks are shown, one green and the other red. The grid spacing is exactly 1 meter, and the times are shown in nanoseconds. The two sticks have a relative velocity, that you can vary, which is a substantial fraction of the speed of light. You may view the animation from the reference frame of either stick. Which stick appears shorter, due to length contraction?

Hints

  1. Vary the relative speed and see how the length(s) change.
  2. Then, view the animation from the other reference frame. What happens? Why?
  3. In which reference frame do you measure the "proper length", L0 , of the green stick?
  4. In that frame, what do you measure as the lengths of the both green and red sticks?
  5. In which reference frame do you measure the "proper length", L0 , of the red stick?
  6. In that frame, what do you measure as the lengths of the both green and red sticks?
  7. What is the relativistic formula for the length that is contracted?

Reference

See Walker, Section 29-3

Illustration written by Steve Mellema