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Section 2.7: Exploring the Pole and Barn Paradox


Please wait for the animation to completely load.

A pole vaulter carries her pole towards a barn as shown in the animation (position is given in meters and time is given in the time it takes light to travel one meter or 3.33 x 10−9 seconds). The pole is seen to be 10-m long when it is moving as seen from the frame of the barn. Also shown above the barn is the spacetime diagram depicting the ends of pole and the barn from two frames of reference. When an object is stationary in a reference frame it is red and when it is moving it is green.  Restart.

Select View from Barn and play.

  1. How fast is the pole moving relative to the barn (measured in c)?
  2. What is 1/slope of the red and green worldlines, respectively?
  3. What do events A, B, A', and B' refer to?  Which if any of these events are simultaneous in this reference frame?

Select View from Pole and play.

  1. How fast is the barn moving relative to the pole (measured in c)?
  2. How long is the pole in this reference frame?  Why is it this long?
  3. How long is the barn in this reference frame?  Why is it this long?
  4. What do events A, B, A', and B' refer to?  Which if any of these events are simultaneous in this reference frame?
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