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August 29, 2008

Strange But True!

Q. Oh, no! The elevator cable snaps and the backup safety system fails and down, down, down you go. How do you optimize your chances of surviving? Would it help to leap up just before the cab collides at the shaft's bottom?

A. Better to drop to the floor and spread out, preferably on your back, which is possible now since there is some drag on the cab from the guide rails, says Jearl Walker in “The Flying Circus of Physics.” The idea is to spread the force you are about to experience over as much body surface area as possible. Standing is ill advised, since under such a collision your ankles will collapse and your body's trunk will crash hard to the floor. Jumping up at the last moment (surely this is impossible to time from an enclosed cab) may be the worst thing you can try since this will only slow you slightly and “if the cab ricochets from the bottom of the shaft you'll be traveling downward as the floor of the cab is traveling upward, and shortly later... Well, no need for the gory details.”


 
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