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adktd2bks
06-23-2009, 12:59 AM
I'm assuming that a fall from either 100 ft or 500 ft would kill you, but would the higher distance cause more bodily damage? i.e., more broken bones, skull cracked in more places, etc? I'm kind of thinking not because the force pulling you down is the same in both cases, but then again I was never very good at physics.

CACTUSWENDY
06-23-2009, 01:10 AM
Tell you what. Give these a try and let us all know how it turns out. lol

I would think that after a certain height all bones would be broken/smashed/blasted to pieces. It would also depend if you landed head first, or on your back, or maybe feet first. (Only my two cents....)

adktd2bks
06-23-2009, 01:15 AM
Tell you what. Give these a try and let us all know how it turns out. lol

I would think that after a certain height all bones would be broken/smashed/blasted to pieces. It would also depend if you landed head first, or on your back, or maybe feet first. (Only my two cents....)

*Bangs head on the table* Of course! Why didn't I think of that!

Parametric
06-23-2009, 01:20 AM
I presume that terminal velocity is a factor. Once you're falling as fast as you can possibly fall, a longer fall shouldn't make a difference to the impact.

Seaclusion
06-23-2009, 01:27 AM
I'm assuming that a fall from either 100 ft or 500 ft would kill you, but would the higher distance cause more bodily damage? i.e., more broken bones, skull cracked in more places, etc? I'm kind of thinking not because the force pulling you down is the same in both cases, but then again I was never very good at physics.


It's not the height of the fall that busts you up, it's the sudden stop at the end.

Richard

blacbird
06-23-2009, 01:28 AM
What parametric said. Falling through air, the human body reaches a maximum velocity at some point (I don't happen to know what that is, but skydivers undoubtedly would), after which it wouldn't matter how far you fell. But, since you asked:

http://hypertextbook.com/facts/JianHuang.shtml

caw

adktd2bks
06-23-2009, 01:28 AM
Thanks. This clarifies what i was thinking.

dpaterso
06-23-2009, 01:35 AM
Terminal velocity is around 120mph, no?

I've heard tales of people surviving falls that should have killed them, e.g. their 'chute didn't open, by aiming for trees, they got pretty bust up but they lived.

Water, struck at terminal velocity, doesn't give way.

-Derek

Julie Worth
06-23-2009, 01:37 AM
Height is definitely a factor for cats. Past a certain number of stories (7), their survival rate goes up, and number of injuries goes down.

Sarpedon
06-23-2009, 01:40 AM
All objects falling through the atmosphere have a terminal velocity. According to Wikipaedia the terminal velocity for a person is 56 m/s. Since objects accellerate 9.8 m/s/s as they fall, it should take approximately 6 seconds to reach a terminal velocity. So in 6 seconds we fall 4.9+14.7+24.3+34.1+44+53.8=175.8m or about 576 feet. So yes, a person falling 500 ft hasn't quite gotten to their terminal velocity. But only barely.

Fenika
06-23-2009, 01:49 AM
I've read that you can survive a fall from 5 or 6 stories up pretty reasonably (assuming ofc you don't land head first). After that, you'd need a miracle or a good haypile/tree/whatever.

adktd2bks
06-23-2009, 02:44 AM
All objects falling through the atmosphere have a terminal velocity. According to Wikipaedia the terminal velocity for a person is 56 m/s. Since objects accellerate 9.8 m/s/s as they fall, it should take approximately 6 seconds to reach a terminal velocity. So in 6 seconds we fall 4.9+14.7+24.3+34.1+44+53.8=175.8m or about 576 feet. So yes, a person falling 500 ft hasn't quite gotten to their terminal velocity. But only barely.

So, if I'm understanding you correctly, then someone who fell from 100ft, which only takes about 2.5 seconds is further from reaching terminal velocity and so the impact might not be as bad as someone who jumped from 500ft? But if you were to compare someone falling from 500 ft vs someone falling from 1000ft there wouldn't be much difference?

This is all being kind of nitpicky I suppose. The reason I ask is that I have a situation where two people are standing outside a ten story window (about 100ft) and one says to the other that he had originally planned to jump from the fiftieth floor because it does more physical damage. Would him saying this make sense or would it be totally bogus?

Cassiopeia
06-23-2009, 02:49 AM
Wouldn't it also depends on the surface they are falling on for the various types of damage you'd find?

rugcat
06-23-2009, 02:59 AM
So, if I'm understanding you correctly, then someone who fell from 100ft, which only takes about 2.5 seconds is further from reaching terminal velocity and so the impact might not be as bad as someone who jumped from 500ft? Yes. Assuming they landed on the same surface, the one from 500 ft would be going faster, thus more damage.

The same model car that hits a bridge abutment at 100 mph is going to sustain more damage than one that hits it at 50. Simple laws of physics.

My last book had someone falling off a cliff. I had to google to find the acceleration formula, then work it out, all for one sentence:

"It takes slightly more than three seconds to fall 150 ft.

James D. Macdonald
06-23-2009, 07:13 AM
A fall of five or six stories? You're kidding, right?

A fall of three times your body height (call it 18 feet) is likely to produce serious injuries.

Fenika
06-23-2009, 07:50 AM
'pretty reasonably' may have been too strong a phrase. But it does happen. Didn't say you wouldn't have serious injuries, just that you might survive.

Dommo
06-23-2009, 11:29 AM
Well while it is true that terminal velocity exists for everything, it's also dependent on the aerodynamic drag of whatever is falling. For example, a parachute my have a terminal velocity of like 10 mph, where as a sleek 2000lb bomb might come down at supersonic speeds.

It all depends, and contrary to popular belief a person can fall significantly faster than 120 mph IF they change their aerodynamic profile(e.g. tuck their arms to their sides, and make themselves like a dart).

Pepper
06-23-2009, 03:26 PM
A fall of three times your body height (call it 18 feet) is likely to produce serious injuries.

My uncle recently fell off a chair (standing on it to sand the roof of his car) and broke 5 ribs. :P All depends on the technique of the fall, I guess, plus other factors such as age, health, etc.


This is all being kind of nitpicky I suppose. The reason I ask is that I have a situation where two people are standing outside a ten story window (about 100ft) and one says to the other that he had originally planned to jump from the fiftieth floor because it does more physical damage. Would him saying this make sense or would it be totally bogus?

It wouldn't be bogus if the character believed that. Just the same as all those suicidal people who watch movies and believe the fastest way to end their life is to cut themselves horizontally across the wrists. Grim example, but it seems to fit your scenario.
Does it really matter if the character's logic is flawed? Should he know all the facts about terminal velocity (or whatever it's called)? Is he a skydiver? If he should know, and he doesn't, you have reason to worry. If he's just an average joe who left school in 6th grade, I don't think the reader will mind if he's got his calculations a little stuffed up. ^_^

And that's my nonsensical rambling quota for the day. :D

Dommo
06-23-2009, 04:14 PM
The trick to committing suicide by jumping is to do one simple thing.

Go head first.

GeorgeK
06-23-2009, 07:55 PM
LD50 for a person falling is 50 feet, meaning 50% of people falling 50 feet will die as a result.

Fenika
06-23-2009, 08:18 PM
omg, they did an LD50 for this?

They did!


> The median lethal dose (LD50) for falls is 4 stories, or 48
> ft, and the
> lethal does for 90% of test subjects (LD90) is 7 stories, or 84 ft.
> Reference: Rosen P, ed. Emergency Medicine: Concepts and Clinical
> Practice. 4th ed. Mosby-Year Book, Inc; 1998:352.

That is good to know.

RJK
06-23-2009, 09:39 PM
They didn't say that the 10% that survived the 7 story fall, all looked like ET afterward.

rugcat
06-23-2009, 09:44 PM
Q. How many writers does it take to change a lightbulb? A. Two. One to screw it most of the way in, and one to supply the final suprise twist.

Ten. One to screw it in, and nine to say, "I could have done that."

Tsu Dho Nimh
06-24-2009, 02:38 AM
I'm assuming that a fall from either 100 ft or 500 ft would kill you, but would the higher distance cause more bodily damage? i.e., more broken bones, skull cracked in more places, etc? I'm kind of thinking not because the force pulling you down is the same in both cases, but then again I was never very good at physics.

Terminal velocity for a human is about 100mph. After that, you don't see more damage regardless of the distance.

You reach TV after about 300 feet of falling, so yes, there would be more damage at 500 feet.

In either case, there's a lot of bone fracture and internal organs are ruptured, skin splits, as can the abdominal wall, skull opens ... they are gory messes.

TabithaTodd
06-24-2009, 02:57 AM
hmm... good question.

There are several dynamics to falling from a set amount of height. The higher, and this is ironic, the better chances of survival - to an extent.

Compare, if you will, a three floor fall to a 6 floor fall. It's been proven from accident statistics that the 6 floor fall is survivable more so than that of a three floor fall because of velocity, impact placement and spreading of impact throughout the body.

The human body is a strange creature indeed, it's amazing how much torture and impact it actually can spread across the frame of both skeletal and muscular persuasion. For instance, take hitting water at a 3 floor height compared to soil...water is like concrete at that height, you can break bones with water more so than you would with soil.

The dispersement of the impact depends on the landing position as well - flat on back, side or stomach? Flat on back with hands and feet spread out is actually safer than side or stomach, especially with the chin tucked forward to prevent the head from slamming on the ground.

It seems, from studies I've seen, that most falls recorded end up with a back landing and on soil or grass rather than concrete or water. I've also seen it said that if you land in water feet first you are likely to shatter shin bones and possibly not so much walk away without multiple fractures of the legs and hips - again water is like concrete theory at play here again.

There's also the other side of the equation - higher falls such as 10 and 12 floor falls can cause internal organ implosions resulting in nearly immediate death through organ failure and internal bleeding. Either way, falls of any height higher than 1 to 2 floors would result in a need for medical attention of the immediate kind.

Tornadoboy
06-24-2009, 06:09 AM
Not to be morbid and it makes me cringe to think about it, but to give you an idea of the kind of damage that can happen at terminal velocity the people who jumped off the WTC buildings essentially exploded when they hit the pavement. People who saw this said there was little left that could be recognized as human and the skin turned purple from all the bursting capillaries.

Thank god it was instantaneous, rest in peace.

adktd2bks
06-24-2009, 06:32 AM
Not to be morbid and it makes me cringe to think about it, but to give you an idea of the kind of damage that can happen at terminal velocity the people who jumped off the WTC buildings essentially exploded when they hit the pavement. People who saw this said there was little left that could be recognized as human and the skin turned purple from all the bursting capillaries.

Thank god it was instantaneous, rest in peace.

Wow. I did not know that. It's kind of like the things you learn about the holocaust -stuff that you know happened but you just don't want to know the details. And, as you said, thank god it was instantaneous.

To everyone else, thanks for all the answers. I now know more far more about falling from high buildings than I ever thought possible.

benbradley
06-24-2009, 08:00 AM
Terminal velocity is around 120mph, no?

I've heard tales of people surviving falls that should have killed them, e.g. their 'chute didn't open, by aiming for trees, they got pretty bust up but they lived.

Water, struck at terminal velocity, doesn't give way.

-Derek
Skyscraper window washers are told "how to fall," to aim for and hit windowsills so every time they hit it slows them down. This can and probably will break bones doing that, but the final speed hitting the ground is much lower, giving a much better chance of surviving. I recall at least one news story of someone who survived a fall doing just that.

Here's someone who survived a 500 foot fall (his brother died in the same fall), though I don't see any indication he used the method I just described (perhaps it was a perfectly vertical wall and he couldn't):
http://www.nj.com/news/index.ssf/2008/01/linden_window_washer_who_fell.html

Height is definitely a factor for cats. Past a certain number of stories (7), their survival rate goes up, and number of injuries goes down.
This has been studied. If the cat has enough time during the fall it can orient itself so its feet hit first and at least partially cushion the impact even at terminal velocity.

Cyia
06-24-2009, 11:50 AM
Also consider the surface onto which the person is falling. While hitting cement would have the "explode" effect, there have been people who hit soft earth and ended up underground. (Horror story from my grandfather about a man who fell out of an open top airplane into fresh tilled dirt.)

Summonere
06-24-2009, 09:11 PM
I'm assuming that a fall from either 100 ft or 500 ft would kill you, but would the higher distance cause more bodily damage? i.e., more broken bones, skull cracked in more places, etc? I'm kind of thinking not because the force pulling you down is the same in both cases, but then again I was never very good at physics.

Assuming the calculations are correct (physics way rusty, here), it certainly looks like distance makes a huge difference:

100 foot fall:
velocity at impact = 55 mph

500 foot fall:
velocity at impact = 126 mph

If we're talking, say, a 200lb guy falling these distances:

100 foot fall, 200 lb guy hits with...
19, 828.14 ft/lbs of force

500 foot fall, guy strikes with a force of...
99,140.7 foot/lbs of force

By the way, I used to 200lb guy as a point of reference because a friend of mine fell about thirty feet while rappelling, landed feet-first, and broke the left foot. This means...

30 foot fall
v = 29.9 mph
force = 5,945.84 ft/lbs.

Spinetinglers
06-25-2009, 09:08 PM
Velocity obviously plays a huge role in whether or not you even survive a fall from height, however I would be in agreement with other posts that how you fall is equally important.

In Belfast we have a company called Harland and Wolff - ship builders, yes think of the Titanic. However they have two very large cranes which dominate the Belfast skyline one is called Goliath and one is called Samson. Samson is the slightly larger of the two having a height of 106 meters which I think is about 350 feet. Goliath is the baby at only 96 meters (approx 315 feet). Over the decades there have been a number of workers who have fallen from the top of these cranes and a large percentage of them survived - one didn't even break a bone! The reason I've mentioned these cranes is because the workers who fell would not have been trained to fall and they have nothing to aim for on the way down to slow their fall. The cranes are obviously on concrete so that takes away any possiblity of a soft landing.

There are too many who have fallen to simply call it luck or coincidence so it must have something to do with the way they've fallen.

On a totally different tangent I have heard stories of people falling from a great height (i.e. out a window several stories high) who were absolutely blind drunk and they survive with only minimal injuries. Could the alcohol they've drunk make their body rely on an instinct that the majority of us have lost as opposed to sheer terror? Hopefully I'll never get to find out but could the sober survivors of falls from a great height have retained this instinct which during the course of evolution has effectively died out in the majority of the population?

FOTSGreg
06-28-2009, 02:17 AM
Here's a paper with the mathematics included to answer your question,

http://books.google.com/books?id=XHnzT9GFu7UC&pg=PA70&lpg=PA70&dq=falling+velocity+vs+injury&source=bl&ots=65u8afdStV&sig=Np0k_-8jlS0u4uv3e32p6NpZD6o&hl=en&ei=SZhGSumCLYT6Mc6dpbQC&sa=X&oi=book_result&ct=result&resnum=2

Basically, it's a collision between a moving object and a non-moving object. You can calculate the force using p=mv or F=ma. You know the mass and acceleration of the falling object so you can do the calculations.

As Uncle Jim said above, it only takes a few fractions of a second falling, ie a fall of a very short distance, for a person to gain enough velocity to inflict major injuries on impact with a non-yielding surface.

In addition, remember that the body in a fall is essentially a big bag of water with a few solid pieces packed inside, essentially a water-filled balloon with some matchsticks inside. Take it up a couple of times its diameter and drop it on a solid surface. You'll start to get a picture of what happens to the human body in a fall. Now, take it up a hundred times its diameter and let it fall.

Now, it also depends heavily on mass of the falling object (hence the F=ma formula).

There's an old saying that goes something like "A mouse dropped down a mineshaft runs away, a human bounces, a horse splashes".

TabithaTodd
06-28-2009, 03:47 AM
Velocity obviously plays a huge role in whether or not you even survive a fall from height, however I would be in agreement with other posts that how you fall is equally important.

In Belfast we have a company called Harland and Wolff - ship builders, yes think of the Titanic. However they have two very large cranes which dominate the Belfast skyline one is called Goliath and one is called Samson. Samson is the slightly larger of the two having a height of 106 meters which I think is about 350 feet. Goliath is the baby at only 96 meters (approx 315 feet). Over the decades there have been a number of workers who have fallen from the top of these cranes and a large percentage of them survived - one didn't even break a bone! The reason I've mentioned these cranes is because the workers who fell would not have been trained to fall and they have nothing to aim for on the way down to slow their fall. The cranes are obviously on concrete so that takes away any possiblity of a soft landing.

There are too many who have fallen to simply call it luck or coincidence so it must have something to do with the way they've fallen.

On a totally different tangent I have heard stories of people falling from a great height (i.e. out a window several stories high) who were absolutely blind drunk and they survive with only minimal injuries. Could the alcohol they've drunk make their body rely on an instinct that the majority of us have lost as opposed to sheer terror? Hopefully I'll never get to find out but could the sober survivors of falls from a great height have retained this instinct which during the course of evolution has effectively died out in the majority of the population?

That actually has a name for it. Being drunk, they are relaxed and supple. The more relaxed you become (ie: perhaps the workers accepted death as they fell, relaxing and just going with it?) the less of an injury you may sustain. It disperses more widely across the body rather than at a point in the body. Kind of like the people who do that stunt with a sledge hammer, slabs of concrete and bed of nails. If it were one nail, wouldn't even get past the laying on the bed of nails bit. One point compared to many.

icerose
06-28-2009, 04:13 AM
On a totally different tangent I have heard stories of people falling from a great height (i.e. out a window several stories high) who were absolutely blind drunk and they survive with only minimal injuries. Could the alcohol they've drunk make their body rely on an instinct that the majority of us have lost as opposed to sheer terror? Hopefully I'll never get to find out but could the sober survivors of falls from a great height have retained this instinct which during the course of evolution has effectively died out in the majority of the population?

Yeah, it really has nothing to do with instinct. Like another poster said it has to do with the body being totally relaxed. It's the same situation with drunk drivers and car accidents. The person most likely to walk away from it is the drunk driver simply because they don't tense up. Where as the people who see it coming tense up and if they survive end up with several broken bones verses the scraped and bruised drunk driver who didn't have enough sense to get scared in the first place.

The paramedics when they came to our school to tell us about drunk driving said that the best thing you can do when you're about to get hit is let go of the steering wheel and slouch in your seat. If you relax your body you're less likely to get hurt. Of course most of us grip the steering wheel, lock our arms, and tense our body. Hence, greater injuries.