- #1
Kruse
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Please excuse me if I seem inexperienced (I am new to this forum), but lately I've been thinking a lot about a length contraction paradox called the Barn-Pole Paradox. The paradox:
A pole and a barn are both at rest relative to each other. When both are at rest, the pole is slightly longer than the barn. However, when somebody picks up the pole and runs toward the barn, length contraction occurs. In the frame of reference to an outside viewer, the runner and the pole both contract, and the pole appears to disappear entirely inside the barn before the runner emerges from the back door (we're assuming in this instance that there is a front door and back door, both of which are open). However, in the frame of reference of the runner, the barn seems to contract, making it impossible for the pole to entirely disappear inside the barn.
I've already read about closing doors and the runner stopping, but here is my question. Let's say that the outside viewer has a remote switch. When the viewer sees the runner and the pole disappear inside the barn, he or she quickly flips the switch on and off. The switch will trigger what has replaced the doors, which instead are electromagnets (we are also assuming that the pole is made of iroin). During this moment that the observer quickly switches the electromagnets on and off, what will happen in the frame of reference of the runner, where the pole is never entirely fit inside the barn?
Thank you for your time.
A pole and a barn are both at rest relative to each other. When both are at rest, the pole is slightly longer than the barn. However, when somebody picks up the pole and runs toward the barn, length contraction occurs. In the frame of reference to an outside viewer, the runner and the pole both contract, and the pole appears to disappear entirely inside the barn before the runner emerges from the back door (we're assuming in this instance that there is a front door and back door, both of which are open). However, in the frame of reference of the runner, the barn seems to contract, making it impossible for the pole to entirely disappear inside the barn.
I've already read about closing doors and the runner stopping, but here is my question. Let's say that the outside viewer has a remote switch. When the viewer sees the runner and the pole disappear inside the barn, he or she quickly flips the switch on and off. The switch will trigger what has replaced the doors, which instead are electromagnets (we are also assuming that the pole is made of iroin). During this moment that the observer quickly switches the electromagnets on and off, what will happen in the frame of reference of the runner, where the pole is never entirely fit inside the barn?
Thank you for your time.