Surviving a falling elevator? - Science, Math and Philosophy Forum

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Surviving a falling elevator?

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07-03-2008 , 03:01 PM

MYSPACETOM

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Join Date: Jan 2008 Posts: 1,119

If you were in an incompressible elevator [built sturdy enough to withstand any structural damage] was falling at a terminal velocity fast enough to kill any human occupants inside, and you were to jump when it was 1m off the ground with enough force to negate the downward velocity, would you survive the fall?

There is 5m of headroom over your head so collision with the top of the elevator is unlikely.

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07-03-2008 , 03:03 PM

mickeyzee

journeyman

Join Date: Mar 2007 Posts: 372

I heard jumping doesn't work. You're supposed to put your back against the wall and bend your knees and try to take the fall.

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07-03-2008 , 03:10 PM

MYSPACETOM

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Join Date: Jan 2008 Posts: 1,119

Quote:

Originally Posted by mickeyzee

I heard jumping doesn't work. You're supposed to put your back against the wall and bend your knees and try to take the fall.

Probably because your legs couldn't exert the force needed to cancel out the velocity?

But if they were?

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07-03-2008 , 03:51 PM

Ringo

grinder

Join Date: Feb 2005 Posts: 581

Mythbusters tested this out, but I forget the exact result. Jumping doesn't work though. It's like the old "If I'm in a falling airplane, and jump out when it's a few feet away from the ground..".

I think by jumping, you'd be making the lift fall a bit faster, in order to give yourself that negative (negative in relation to the lift at least) velocity. If you were strong enough, maybe you could change your velocity significantly in relation to the ground, which is what really matters. If the lift was plummeting at 8m/s, jumping might let you smack into the ground at 7m/s, if you timed it perfectly, if you were strong enough, etc etc.

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07-03-2008 , 04:33 PM

KCW12

grinder

Join Date: Jul 2007 Posts: 677

Assuming you were strong enough to give yourself just enough momentum to momentarily leave you at rest, yes this would work in theory. No human could come close to generating that much energy though. Actually, now that I think about it more, you must not only assume the elevator is able to stay intact and uncompressed during the impact, but it must land on a surface such that it doesn't bounce appreciably or create a deep crater, otherwise 5m of headroom may not be enough.

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07-03-2008 , 04:38 PM

Flamingo

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Join Date: Aug 2007 Posts: 446

http://en.wikipedia.org/wiki/MythBus...vator_of_Death

I knew I've seen this episode. Jumping doesn't work. Brace yo self.

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07-03-2008 , 04:44 PM

mickeyzee

journeyman

Join Date: Mar 2007 Posts: 372

Quote:

Originally Posted by MYSPACETOM

Probably because your legs couldn't exert the force needed to cancel out the velocity?

But if they were?

http://zebu.uoregon.edu/~probs/mech/.../elevator.html

Theres a problem with solutions

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07-03-2008 , 05:25 PM

thylacine

Pooh-Bah

Join Date: Jul 2003 Posts: 4,029

Your momentum would change by the same amount no matter what.

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07-03-2008 , 07:24 PM

kevin017

old hand

Join Date: Mar 2005 Posts: 1,299

if your legs could exert enough force then sure you'd be fine. but if your legs could exert that much force you wouldn't have to jump at all i don't think, you could just land and your leg muscles would be able to handle the impact.

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07-03-2008 , 07:32 PM

#10

thirddan

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Join Date: Nov 2003 Posts: 11,695

the wiki page linked above says you should lie down...wtf?

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07-03-2008 , 07:35 PM

#11

Max Raker

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Join Date: Apr 2005 Posts: 15,738

Quote:

Originally Posted by thylacine

Your momentum would change by the same amount no matter what.

That is not the only relevant parameter.

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07-03-2008 , 07:41 PM

#12

Max Raker

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Quote:

Originally Posted by thirddan

the wiki page linked above says you should lie down...wtf?

Thats what I would guess, try to maximize air resistance and provide the largest possible area so the max force that any part of your body feels is minimized. There could be details of the human body which could make this incorrect though.

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07-04-2008 , 01:40 AM

#13

sumpy

adept

Join Date: Dec 2007 Posts: 1,159

Quote:

Originally Posted by kevin017

If your legs could exert this much force, than what are you doning on the elevator at all? Just jump out the window, you'll be fine, and it would be a lot faster.

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07-04-2008 , 02:25 AM

#14

kevin017

old hand

Join Date: Mar 2005 Posts: 1,299

Quote:

Originally Posted by sumpy

If your legs could exert this much force, than what are you doning on the elevator at all? Just jump out the window, you'll be fine, and it would be a lot faster.

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07-04-2008 , 02:42 PM

#15

Nulle

centurion

Join Date: Oct 2007 Posts: 157

Fast acceleration is lethal. If your legs could exert that much force, would the jump kill you.

Last edited by Nulle; 07-04-2008 at 03:10 PM.

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07-05-2008 , 02:40 PM

#16

Flamingo

grinder

Join Date: Aug 2007 Posts: 446

Quote:

the wiki page linked above says you should lie down...wtf?

Ya, I'm with you. I don't want to go out that way.

But, lying down makes sense. There are going to be enough vertical g's that anything standing upright will break. Nobody likes dying lying down, but you're screwed. You have to forget any notion of getting out without a scratch.

It's funny that the MythBuster's site had their own wiki that was incomplete and WikiPedia has the episode complete. Wiki pretty much pwned.

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07-05-2008 , 10:36 PM

#17

MYSPACETOM

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Join Date: Jan 2008 Posts: 1,119

Lying on the elevator floor is just so wrong on so many levels. You want to protect your skull and central nervous system (spine) while falling. Placing both your head and your spine in direct contact with the floor which will transfer most of the impact velocity into those parts is just nonsense.

That's why falling on your legs is such a good idea, sure you'll break them but they slow you down alleviating a lot of the force placed on impact.

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07-06-2008 , 02:36 AM

#18

Max Raker

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Quote:

Originally Posted by MYSPACETOM

I think if you fall on your legs you will certainly break your back. Obv having your head hit first is just plain wrong, but I dont think that is what they are saying to do.

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07-06-2008 , 02:57 AM

#19

Flamingo

grinder

Join Date: Aug 2007 Posts: 446

I think they mean lying down in the fetal position. I wouldn't want to sit in the corner holding on, because that would probably break my back.

Regardless you're probably going to die, but your chances are relatively better lying down according to the MythBuster's experiment. I'd have to see the episode again to see exactly how to lie down properly (if they went into that much detail.

Anything that's upright is much more likely to break I'd imagine.

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07-06-2008 , 08:16 AM

#20

tame_deuces

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Join Date: Oct 2005 Posts: 18,254

Well breaking is one thing...

But if we imagine a fall from say...10 meters and onto concrete, do you want to land spread out and flat on your back?

I don't think the survival chances are high nomatter how you land, but it would seem to me that the legs when breaking can provide cushioning to the vital organs in the torso and head. Though I'd guess thigh arteries that rupture is probably going to finish you off rather quickly even if you get "lucky" in most cases.

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07-06-2008 , 08:44 AM

#21

madnak

Cooler than Sammy Hagar

Join Date: Aug 2005 Posts: 19,742

Is there any major physical difference between falling in a container (such as an elevator) and falling directly onto the ground?

I know some people have fallen from airplanes and landed with only superficial injuries. I've always wondered at the physics of that. I'm sure it has something to do with elasticity.

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07-06-2008 , 09:12 AM

#22

mute

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Join Date: Apr 2005 Posts: 11,815

See 0:59 in.

http://ie.youtube.com/watch?v=Gqd2MZ...eature=related

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07-06-2008 , 10:18 AM

#23

tame_deuces

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Join Date: Oct 2005 Posts: 18,254

Quote:

Originally Posted by madnak

If we assume the concrete is immovable, then it should be fairly equivalent of standing in a falling elevator that won't take structural damage (like the OP) - it's your body that will have to cushion the impact.

Other than that in the real world a "container" can cushion an impact (and hopefully you don't die from its collapse).

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07-06-2008 , 10:54 AM

#24

PLOlover

Pooh-Bah

Join Date: Jun 2005 Posts: 5,552

is there an analogy with car seat belts? could there be some sort of "elevator belts" in theory?

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07-06-2008 , 03:53 PM

#25

Max Raker

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Join Date: Apr 2005 Posts: 15,738

Quote:

Originally Posted by tame_deuces

I think from heights of this order you are supposed to do a tuck and try to roll when you hit the ground. If you can increase the time over which you decelerate you have a better chance of avoiding injury.

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