- A relativistic pole-vaulter is carrying a pole vault which is 10 meters long and is running very close to the speed of light towards a garage 5 meters long with open doors at both the front and back of the garage. Two demons decide to have some fun. The demon on the exit door shuts his door. The demon on the entrance door slams the door shut just as the pole of the pole vaulter moves past. Just an instant later the demon at the exit door opens his door, allowing the pole vaulter to escape (though seriously scared!). However, for an instant, the demons agree that both the pole and pole-vaulter were enclosed inside the garage. The reason that a 10 meter long pole can fit into a 5 meter long garage is that:
B. The pole vaulters clock is running slow because he is going fast
C.The demons see the moving pole to be short.
D.The garage is longer than 5 meters because it is at rest