Just because lifts (elevators) can’t free fall doesn’t mean people don’t die in them. There’s been at least 2 in the UK in the past 12 months
This isn’t accurate. Even though your head is already on the floor of the elevator when it hits the ground, the energy transfer is exactly the same (or very nearly so, minus damping effects if the elevator floor is softer than the ground, for instance if it is carpteted) as if your head hit the ground directly. The injuries caused by the two events would be indistinguishable. This is nonintuitive so it bears explanation:
What happens when you fall off a building and land, say, on your head? Your head strikes the ground, and the electric repulsion between the electrons in your head and the electrons in the ground prevent your head from penetrating said ground. the rapid deceleration results in a very high G-force, effectively causing your head to weigh many, many times its static weight, and it is this which causes the injuries, since your skin and skull aren’t designed to hold up to thousands of pounds of force. The effect would be identical to putting the same amount of weight on your head. Now you can see this is the same situation in the elevator: even though your head is on the floor of the elevator, when the elevator hits the ground, there is the same deceleration, and therefore high Gs, as the case of you falling freely from the same height (again, minus and damping effects present). So there you have it. The best you can do if the elevator falls from a sufficient height is put your head between your legs and kiss your butt goodbye.
To look at it another way, if putting your head on the floor protected you, so would gluing a steel plate to your head.
What if you were just lucky enough to have something large and soft with you, like, say, a new mattress you had just bought and you were taking it up to your penthouse apartment? Would the mattress save you, or would you bounce back up off of it and hit the ceiling of the elevator with full force like they do in cartoons?
The mattress would cushion the impact, certainly. Whether it would save you or not depends again on the velocity at the time of impact, as well as the physical properties of the mattress. Do you think you could survive, say, a five-story fall off a building if you landed on a mattress on the ground below? A ten-story fall?
Yes, much slamming involved.
Try this; Take a piece of drywall and affix it to your forehead. Now run into the nearest wall headfirst. Did that hurt? Or was your head “already against the wall” therefore preventing injury.
Didn’t an elevator plummet with a woman in it when that bomber crashed into the Empire State Building?
It started to, but the Otis safety device saved them:
From here.
What about personal airbag suit…pull the rip cord and be come an oversized ping pong ball…Doing! :eek:
Now we’re just getting silly.
Sorry :rolleyes: wasn’t trying to take away from the convo
Silly? A personal airbag suit could come in handy for all sorts of dangerous situations.
Like, you know when that annoying close-talker starts encroaching on your personal space? Just pull the rip cord and blast him back to his own cubicle 
A nitpick for QED: Falling headfirst from a building isn’t the same as laying down in a falling elevator. In the first scenario, your head is the first point of contact with the ground for the entire mass of your body, while in the second each body part that touches the floor of the elevator supports its own mass. If you remain standing, your legs will take much of the impact shock, but that’s what legs are good for so it may be the best way to go.
If you were lucky enough to be lying on it when the cable snapped, then it might help a little (but probably still not enough - look at the size of those airbags that stuntmen use), but otherwise, you simply wouldn’t have time to move it into position, especially in near-free fall.
Here’s some empirical-type dope on the matter, from the elevator guy:
http://www.elevator-world.com/magazine/archive01/9603-002.htm
If, for whatever reason, the safety features were disabled and the elevator car went into full freefall, you would essentially be floating in the car. It would be difficult to position yourself into whatever position you thought was best without the normal assistance of gravity.
There is some improbable TV show in which improbable scenarios are laid out and improbable mitigating actions are given – all with the improbable rationale that you could protect yourself. It’s called “What’s the Worst That Could Happen” or something. They did a little deal on this, and thier “expert” said to lean into a corner and brace yourself. They somehow demonstrated it and the guy was forced from leaning into a crouching stance by the impact.
Back in physics class it was common to get a problem involving the parameters of a spring required to stop a falling elevator of weight X without imparting a force greater than Y on the occupants.
Has an elevator ever been designed with an arresting spring at the bottom? I would assume it would have a false floor above it on tracks so you could walk on it, etc. But could it be done?
My guess is that there’s no reason to ever do it, because elevator designs are positively safe anyway. System failures cause the automatic engagement of brakes, and it’s not plausible that a cable and four independent brakes would all fail at the same time.
I happened to look into the shaft of an elevator under repair (from the first floor – not very dangerous) of a 10-story dorm at the University of Kansas. The shaft extended approx. 4 feet below the lowest level, and there were four heavy-duty springs. If memory serves (and it probably doesn’t), the springs were a coil maybe 10"-1" in diameter and a couple of feet high.
They didn’t look big enough to keep a elevator in true free-fall descending from the 10th floor from actually hitting the ground – just slowing it down a little, then give the twisted and bloody remains a little bounce.
But it is hard to tell the spring factor just by looking. But if the springs could actually stop the 'vator before the springs were fully compressed, it would be a very fast accelleration.
That’s just a damn good question I’d love to know the answer to. I’ve been looking for stories (heh) about the famous elevator free-fall in the Empire State Building (bomber hits building, cleaning lady falls 78 or 81 stories, depending on the tale).
I’ve read from various sources that a) there was a spring at the bottom, b) there was not a spring at the bottom but that the coiling cable acted as a spring :dubious: , c) the shaft was tight enough that compressed air acted as a brake, d) the normal safety systems worked well enough to slow the car and e) we don’t know why the lady lived.
If someone could get the true Straight Dope on the story (here’s one recounting to get you started), that would be a nice blow against ignornace.
The absolute worst thing you could do would be to spread yourself flat on the bottom. You’ve got a change in velocity, which you can’t do anything about. You want to minimize the acceleration, since it’s the acceleration that kills you. Since acceleration is change in velocity over time, you want therefore to maximize the time that you spend on that change in velocity. Which means start off standing up, let your legs and lower body use up as much of the velocity as possible, and end up flat on the ground. Handholds on the top would be even better: Start off hanging from the top with your arms pulled up as much as possible, use up velocity in extending (and probably hyperextending) your arms, then hit with your legs.