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Q & A: If you’re in a falling elevator...!

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Most recent answer: 10/22/2007
Q:
Say you were in an elevator, in a free fall. Assuming you have the presence of mind in this situation, and assuming you get the timing right and jump so that you are up in the air when the elevator hits bottom, would you be hurt as much as if you hadn’t jumped? Thanks.
- J.K. (age 18)
Urbana, IL, USA
A:
Great question! How much you get hurt depends on the force on you when you hit the ground. Remember that force is proportional to the change in momentum and inversely proportional to the length of time over which the momentum changes.

Since momentum is mass times velocity, the faster you're going when you hit the ground, the more force you will feel, and the more it will hurt. If the elevator has been falling for a while, then it's probably moving very fast. If you jump up, then you'll change your velocity just a little bit. So you'll be going a tiny bit slower when you hit the ground. So, technically speaking, you would probably not be hurt quite as much. But this difference would probably be so small as to not be noticeable. In particular, if you're falling so fast as to be killed in the fall, jumping would most likely not make enough of a difference to save your life.

-Tamara

(published on 10/22/2007)

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