Highest Non fatal jump?..

[Challenger78]

What's the highest height a human can jump from without critically injuring himself ?,
I heard that it's roughly 3-5m, depending on your height. Somehow I doubt that's the case.

[Absane]

Pregnant, topless skydiver falls 10,000ft and LIVES.. and so does her unborn baby

http://www.mirror.co.uk/news/tm_objectid=16481740&method=full&siteid=115875&headline=oh-chute--name_page.html

http://images.mirror.co.uk/upl/m2/dec2005/1/0/000891CA-D60C-139F-98470C01AC1BF814.jpg

[Nasor]

[I]Pregnant, topless skydiver falls 10,000ft and LIVES.. and so does her unborn baby
What the stupid british article fails to mention is that her parachute DID partly deploy, and did slow her down significantly. It just didn't deploy completely, so she hit a lot harder than she should have (but still much slower than if the parachute hadn't opened at all). Apparently this "newspaper" left that little detail out simply to try to make the article more interesting.

[chris4355]

What the stupid british article fails to mention is that her parachute DID partly deploy, and did slow her down significantly. It just didn't deploy completely, so she hit a lot harder than she should have (but still much slower than if the parachute hadn't opened at all). Apparently this "newspaper" left that little detail out simply to try to make the article more interesting.

So she doesnt count.

Interesting question, I tried finding something on google but nada.

[PieAreSquared]

http://en.wikipedia.org/wiki/Vesna_Vulovic

[chris4355]

http://en.wikipedia.org/wiki/Vesna_Vulovic

wow, even comes with an interesting back story.

thanks.

going a little out of topic...

it looks like that event sparked her life and in an odd way was actually a good thing...

I am curious to know how she actually survived it though. In any standard conditions such a fall is not doable...

[PieAreSquared]

I think she landed on a snow covered slope and slid down

[PieAreSquared]

Just wondering did the highest sky dive record get broken yet.. there was someone who was attempting to break it recently

http://en.wikipedia.org/wiki/Highest_sky_dive

[Nasor]

wow, even comes with an interesting back story.

thanks.

going a little out of topic...

it looks like that event sparked her life and in an odd way was actually a good thing...

I am curious to know how she actually survived it though. In any standard conditions such a fall is not doable...
She was inside a big section of plane fuselage that fell out of the sky. I'm not sure if that "counts" or not.

[PieAreSquared]

http://www.greenharbor.com/fffolder/wreckage.html

[chris4355]

http://www.greenharbor.com/fffolder/wreckage.html

^^ nice!

[Challenger78]

We all sprain ankles if we jump from mid level/ off a fence. I'm guessing damage to height graph isn't linear.

[Absane]

We all sprain ankles if we jump from mid level/ off a fence. I'm guessing damage to height graph isn't linear.

Depends on how you land and how the energy is distributed.

The energy of an impact is proportional to the distance. You could, in theory, sprain an ankle from a fall of only 6 inches if you concentrate all the energy on the joint. But you can fall 2 meters onto your back and walk away.

[Nasor]

Heck, you can sprain an ankle simply putting your own body weight on it wrong from a height of zero meters.

[Absane]

Heck, you can sprain an ankle simply putting your own body weight on it wrong from a height of zero meters.

If you are weak. I can stand on my ankle with my right foot no problem.

But I don't think I should be doing that...

[Asguard]

there is no "fatal height", it depends on alot of things.

f=ma2
impulse =F delta t

it depends mainly on the last equasion, for instance there are cases of WW2 pilots who fell out of their planes onto frozen rivers anf survived because rather than a dead stop they slid along the ice. similar situation is falling on really soft ground where the ground acts like the crumple zones in a car.

as a rule of thumb 3 times the persons height is champions criteria which is a grading scale for major truma

[Fraggle Rocker]

What's the highest height a human can jump from without critically injuring himself ? I heard that it's roughly 3-5m, depending on your height. Somehow I doubt that's the case.Indeed. Just last night someone was telling me that 30ft (9m) is the 50th percentile, i.e. that if you fall from that height you have a 50-50 chance of surviving.

[Xylene]

There was a British crewman of a Lancaster bomber during the war who jumped out of his burning 'plane over Germany and went to pull the rip-cord, which came away in his hand 'cos the parachute was burned and useless. Oh my God he thought, I'm done for, but he landed in a deep snow drift (having fallen ca. 22,000 feet) and all he got was a broken ankle. When the German troops caught him, he told them what had happened. Rubbish, they said; prove it. So he took them back to where he landed, and showed them the hole he made in the snow...they were duly impressed, I daresay.:)

[Asguard]

there was a paratrooper in WW2 who was drooped into germany and had a pain his neck after landing. he fought fo a short while and was captured and locked up in a very small room forcing him to lay down for months on end. years later he had a c-spine xray and it turned out he had an old healed fracture at c1-2. the fact that he was forced to lay down for so long it savec his life by alowing it time to heal.

really amazing

[MRC_Hans]

Obviously, if you have some sort of 'parachute' be it plane wreckage or whatever, and something to take some of the energy from the landing, be it a soft spot on the ground or something like that, you can survive falls from basically any hight.

The terminal velocity of a falling human is around 230km/h, which is reached after a few seconds of falling. Once you have reached that speed, you won't fall faster, just longer. Various things (like parachutes) can lower the terminal velocity.

A trained person can, of course, jump from greater heights than a non-trained. Apart from being stronger, the trained person can employ various techniques to divert the forces of impact, for example by deflecting into a roll.

And, of course, the type of ground you hit makes a lot of difference; a thick layer of grass makes for a much softer fall than a layer of concrete. Incidentally, if you have to jump from a dangerous hight, try to aim for the roof of a parked car. First of all, your fall will be reduced by the hight of the car, and the buckling roof will absorb quite a lot of the energy. Many people have, intentionally or not, survived jumps from burning buildings that way.

Hans

[Challenger78]

Interesting. Cars. So Jumping on a bus is even better ?.

[Nasor]

there is no "fatal height", it depends on alot of things.

f=ma2
impulse =F delta t

it depends mainly on the last equasion
Impulse is not a useful number. Your impulse will always be the same for a given velocity change, regardless of how long the velocity change takes. Going from 100 km/hour to 0 km/hour in your car will always have the same impulse, regardless of whether you do it in 0.01 seconds by cashing into a tree or 10 seconds with your brakes.

I think the acceleration experienced in the crash is what you need to look at.

[Asguard]

no its not, your ignoring a whole section of the equasion, ie "delta t", t is time. ie impulse is inversly proportion to the length of time. if you slow down from 500 km\hour OVER 1 hour thats a MUCH smaller impulse and there for smaller force than 100 in 0.001 second

[Nasor]

no its not, your ignoring a whole section of the equasion, ie "delta t", t is time. ie impulse is inversly proportion to the length of time. if you slow down from 500 km\hour OVER 1 hour thats a MUCH smaller impulse and there for smaller force than 100 in 0.001 second
No offense, but this is very basic physics.

A 10 kg object goes from 10 m/sec to 0 m/sec in 1 second. The acceleration = velocity change/time = 10 m/sec^2. The force = mass*acceleration = 100 N. Impulse = 100 N * 1 sec = 100 N sec.

A 10 kg object goes from 10 m/sec to 0 m/sec in 100 seconds. The acceleration is 0.1 m/sec^2. The force = mass*acceleration = 1 N. Impulse = 1 N * 100 sec = 100 N sec.

You can try it with any time period, velocity change, or mass you like; for an object of a given mass that undergoes a certain change in velocity, the impulse will always be the same regardless of the time. Any increase in time will be associated by a decrease in force that exactly cancels out the effect of the longer time period.

Edit: also, look at your own equation that you posted. Impulse is not inversely proportional to time, it's directly proportional to it. Longer time = larger impulse, assuming the force stays the same.

[MRC_Hans]

Interesting. Cars. So Jumping on a bus is even better ?.Would reduce your hight more. OTOH, I suspect that the roof of a bus is much harder. Also, I forgot to mention that the suspension of the car will take up some energy. Not so for the bus (because your weight is a much smaller fraction of the weight of the bus).

But the bus is, of course, much easier to hit ;).

Hans

[Challenger78]

No offense, but this is very basic physics.

A 10 kg object goes from 10 m/sec to 0 m/sec in 1 second. The acceleration = velocity change/time = 10 m/sec^2. The force = mass*acceleration = 100 N. Impulse = 100 N * 1 sec = 100 N sec.

A 10 kg object goes from 10 m/sec to 0 m/sec in 100 seconds. The acceleration is 0.1 m/sec^2. The force = mass*acceleration = 1 N. Impulse = 1 N * 100 sec = 100 N sec.

You can try it with any time period, velocity change, or mass you like; for an object of a given mass that undergoes a certain change in velocity, the impulse will always be the same regardless of the time. Any increase in time will be associated by a decrease in force that exactly cancels out the effect of the longer time period.

Edit: also, look at your own equation that you posted. Impulse is not inversely proportional to time, it's directly proportional to it. Longer time = larger impulse, assuming the force stays the same.

I thought impulse was the change in momentum over time, the greater the time, the smaller the impulse ?

[Nasor]

I thought impulse was the change in momentum over time, the greater the time, the smaller the impulse ?
No, the impulse is simply Force x Time. A longer time = larger impulse. The impulse is equal to the total change in momentum. A given change in momentum will always equate to the same impulse, regardless of how long the momentum change takes. Note that momentum and impulse have exactly the same units (kg m/sec). That's why the impulse is the same regardless of whether you decelerate very quickly by crashing into something, or very slowly with your brakes. Which is why impulse is a useless number for determining how dangerous a crash is.

[Absane]

Actually,

\mathbf{I} = \int \mathbf{F}\, dt = \Delta\ p = mv_1 - mv_0

So, Nasor is right... impulse is the same regardless of time.

[Ophiolite]

If you do have to jump from a burning building onto a car I recommend aiming for a 4x4. That way, even if you don't survive, you'll have inconvenienced the prick who owns it.

[Challenger78]

If you do have to jump from a burning building onto a car I recommend aiming for a 4x4. That way, even if you don't survive, you'll have inconvenienced the prick who owns it.

Well said.

[Challenger78]

No, the impulse is simply Force x Time. A longer time = larger impulse. The impulse is equal to the total change in momentum. A given change in momentum will always equate to the same impulse, regardless of how long the momentum change takes. Note that momentum and impulse have exactly the same units (kg m/sec). That's why the impulse is the same regardless of whether you decelerate very quickly by crashing into something, or very slowly with your brakes. Which is why impulse is a useless number for determining how dangerous a crash is.

how about Ek=1/2 mv2..

P.S. Can you put superscripts into this thing ?

[Absane]

how about Ek=1/2 mv2..

P.S. Can you put superscripts into this thing ?

E_{k} = \frac{1}{2}mv^{2}

TeX is so freaking cool. It's weird to see outside of the Math/Physics forum though.

[Nasor]

how about Ek=1/2 mv2..

P.S. Can you put superscripts into this thing ?
The change in kinetic energy is also same regardless of how long it takes you to slow down. Like I said before, acceleration seems to be the main thing that would determine how damaging a crash is, because the acceleration will be directly proportional to the force experienced during the crash. Although even that isn't perfect, because I'm sure the damage to your body gets worse for a given acceleration as the time that you experience it gets longer. So really I don't think there is any magic number that you can derive to determine how dangerous a crash is. You would need to look at both the acceleration and the time that the victim experienced it.