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Effects on the human body after a fatal fall
anime_angel_ash wrote in little_details
Setting: 1920's London, though I don't think that'll have much bearing here.

Question:In a short story I'm currently working on, a character falls from an extremely great height (roughly jet altitude, though this is achieved through magic rather than being in an actual plane) crashes through the roof and second-story floor of the house, and obviously does not survive the impact with the ground. Her body is discovered several hours later by another character, to whom this section of the story is sympathetic. My question is, what would the body look like after such an impact? Obviously she would not be in good shape but what, specifically, would have happened to her? Also, would her body be able to go through the second-story landing after the impact with the roof, or would it slow her descent enough to make that impossible?

Questions Googled: I was a bit of a loss as to how to go about this one. I tried "human body + impact with ground" "what happens to the human body when it hits the ground" and variations thereof and was not able to find anything particularly useful. I was not sure how to add in the necessary part about her crashing through the house. Any help on such would be great.

While I don't know how completely accurate the science is on the tv show Bones, there was an episode that involved a body falling from extreme heights. Here's the transcripts of that episode, it might help.

Edited at 2009-10-13 02:50 am (UTC)

You might want to consider what height planes were able to get to in the 20s, surely not the same as today.

She is actually not in a plane when this happens. It's difficult to explain, but really it comes down to magic being involved in getting her to that height before things go horribly wrong.

I just googled a bit in my native language, and it appears that there is a maximal speed someone can reach while falling from a plane, which is between 200 and 300 km/h, due to the resistance factor of the air. It appears that once you reach a certain height, any height differences don't matter much, so the old planes wouldn't necessarily give you less speed. The information I found (all in forums where someone asked a similar question) was all somewhat speculative, but several people said that when impacting into the ground, depending on the position someone impacted in, they could make a hole as deep as 70 cm, which seems to indicate that the forces reached might be sufficient for going through the landing. Basically, from falling at that speed, her body weight would be "multiplied" many times on impact, meaning that she would create the same effect as a much heavier object impacting from a smaller height. My physics skills are too rusty to calculate exactly.

Oooh, thanks! That clears that up.

Not an expert here, but a good phrase is "terminal velocity". The force she'll exert on the roof has to do with her mass, basically (assuming she reaches terminal velocity before impact, which is likely at that height.)

A falling person will achieve terminal velocity in about 6 seconds, or about 180 meters.

As for the physics, the falling body has a combination of mass and speed which can be described as either energy (E=1/2 mv^2) or momentum (p=mv). When that body hits the ground, the interaction of the ground with the falling body generates a force. This force can be described as the integral of the change in momentum with respect to the time of that impact, or by the derivative of energy with respect to the distance the falling body penetrates the ground. Depending on your approximations you'd get the same answer in either case but for energetic impacts like this, energy is more useful.

You're right the ground (and the falling body) would feel a force similar to having very heavy weight, and that force will jump up and drop down very quickly as the energy of the falling body is spent by distorting the body and the ground.

The actual forces and depth of distortion of the ground depend entirely on what the ground and the falling body are made out of.

What comes immediately to mind is the bombing of Pan Am 103 over Lockerbie, although I confess I don't have a strong enough stomach to pursue the inquiry...

There is also information about the people who jumped from the World Trade Centre on 9/11. From documentaries I've seen, the bodies of those poor people were usually not intact after the fall - the bodies were not shown but the reactions of the individuals who saw the bodies was.

From what I know of Lockerbie, the condition of bodies varies according to what the people fell on to, and also whether they were still strapped in a seat and cushioned from impact. At least one person was alive after impact, but died before being reached by medical help.

In this case, I imagine the body will be covered by bits of smashed house. Even if it is not actually externally injured by the impact, it may still be injured by bits of flying roof tile etc.

This may sound strange, but, check out Mythbusters. There is one in particular where they tested a myth about a skydiver, whose parachute failed, falling onto a teeter-toter and throwing a little girl sitting on the other side (unharmed) onto a naighboring roof top cartoon style. Rather than using Buster, they filled an inner tube with sand, then stuffed that in a duffel bag. it exploded on impact. Several myths involving falling also include a nice breakdown on terminal velocity and how it's calculated.

basically, I think he'd be hamburger. (also, check the shoes flying off the little girl dummy, awesome! and a couple explanations, the see-saw looks the way it does because the first time they tried it, with a store-bought metal see-saw, it just broke, so they made a super-see-saw based on a crane to wisthstand the forces. the big cord is a bungee-cord, which they used to mimic terminal velocity with the precision needed to hit the small target)

*edited to add, they've also done other tests with either Buster wearing impact sensors to show what bones broke etc. or ballistic gel dummies with skeletons and blood packs inside, but I can't remember which specific episodes used each. the ones with the ballistic gel dummies would probably be most useful to you.

*edited to add 2: found the episode on youtube

Edited at 2009-10-13 06:14 am (UTC)

It depends how she lands as well - if she landed on her head, her skull would basically be smashed in, neck broken and chances are her face would be almost unrecogniseable. If she landed feet first of course she would have compound fractures of the legs, knees, pelvis, but she may even survive. If you're more relaxed when you land, the injuries can be reduced (e.g. if you're very drunk, you have a much greater chance of surviving a fall from a great height), because you're not tensed against the impact so there's less jarring. From what I know of it, most of the injuries would be internal, apart from post mortem bruising that would be showing up by the time the other character found her, except where a compound fracture of bones or something jagged as she crashed through the roof cut her skin.

Hitting the roof would break some skin, but a fall in itself would not cause skin rupture necessarily so her body might be relatively intact. For example, Teoh Beng Hock fell 9 stories onto a hard concrete roof of an adjoining building, and there was no blood at the scene at all - he had fatal internal injuries, as all his organs would have jarred terribly and ruptured when he landed, but the outside of his body looked intact. That's not far enough to fall to reach terminal velocity, but still, it goes to show that serious falls don't necessarily leave someone 'splattered across the pavement' as it were.

So IMO, you have freedom to decide how you want her to be injured, but as a rule... her body would retain general structural integrity, but the bones around the area where the impact(s) occurred would be shattered, and she'd have massive internal injuries. I don't know if that's any help or not.

You're probably going to want to think about the structure of the house roof, just to complicate things even more. There are joists, and things... I suspect the body would have to go between them rather than through them if you want it landing on a the top floor rather than partly in the loft/attic.



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