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# physics > G force > 350 G's and 10,000 feet

Posted on 2012-12-27
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Falling object from 10,000 feet reaches 350 G's at impact.
Any living creature still conscious at that point?
Would an animal die of:
a. drowning.
b. the impact.
c. the 350 G's in such a short time frame.
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Question by:nickg5
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Accepted Solution

TommySzalapski earned 400 total points
ID: 38725053
How did you get that number?
You need to neglect air resistance to get very fast when falling (read up on Terminal Velocity).
If there is no air, you won't feel any force until landing.
If there is air, then all the terminal velocity stuff comes in and you would feel the force of the air, but it would not be more than 1 g.

The force felt on impact is inversely proportional to the time it takes to stop falling. So you would need that to calculate the force.
If you stopped instantly, you would feel infinite force and be instantly flattened to flatter than a molecule.
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LVL 25

Author Comment

ID: 38725262
Swiss Air Flight 111, 1999. A you-tube video stated that the pilots lost control due to an internal fire and the plane plowed nose down into the Atlantic Ocean at 350 G's of force.

So, yes there was air, but the distance was 10,000 feet and the G's at impact were 350.

If all survived the G forces then they drowned or died on impact.
It was one plane, 228 persons, say 750 pieces of luggage, say 500 pieces of other cargo.
The result was over 1 million pieces, so yes 300+ G's at impact.

So, the speed during those 10,000 feet resulted in over 300 G's of force.
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Assisted Solution

d-glitch earned 400 total points
ID: 38725502
If the plane is really falling (rather than power diving), then it is accelerating at 1 g (or less due to air resistance) until it hit the water.  People in the plane are closer to free fall (zero g) then anything else.

g force at impact is hard to estimate.  It depends on the final velocity and on how the plane crumples.
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LVL 84

Expert Comment

ID: 38725809
David Purley survived an estimated 180g when he crashed in 1977
Bacteria have been cultivated in an ultracentrifuge  at 403627g
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Assisted Solution

BigRat earned 400 total points
ID: 38726676
>>So, the speed during those 10,000 feet resulted in over 300 G's of force

Strickly speaking the momentum. The speed will be limited by air resistance, assuming a free fall, which will produce a fixed amount of momentum.

When two objects collide the total momentum is distributed between the objects according to their masses less that amount of momentum which disappears in heat. This loss is determined by the coefficient of restitution.

Most man made objects, like cars and planes crumple on impact, that is the coefficient of restitution is very low. Water is in fact a very hard substance (it is almost incompressible), so the aeroplane's impact would probably result in the crumpling of the entire plane. The time of the crumpling would be somewhere just short of assuming that the tail section continued with the same velocity until that hit the water. This would give the period of time in which the total momentum gets converted to heat (since the coefficient is so small) and that divided into the total momentum (mass of the plane times the velocity) would give the force of impact.

The answer to the question is "the impact", since the crumpling of the aircraft would apply to all inside - one might simply be crushed to death - which happens in high speed car accidents where the engine gets shoved into the passenger compartment.
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Assisted Solution

ozo earned 400 total points
ID: 38726815
Free falling in a vacuum at 1g for 10,000 feet, and then a perfectly uniform stop in 28.57 feet would produce 350g
Falling slower and a stop in a shorter distance, or a nonuniform stop could also produce 350g.
350g for more than an instant would be enough for human arteries to get shoved out of ones heart.
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Assisted Solution

aburr earned 400 total points
ID: 38729409
Ozo's comment
"Free falling in a vacuum at 1g for 10,000 feet, and then a perfectly uniform stop in 28.57 feet would produce 350g
Falling slower and a stop in a shorter distance, or a nonuniform stop could also produce 350g.
350g for more than an instant would be enough for human arteries to get shoved out of ones heart. "

is the most relevant. It clearly shows that 350 gs would cause the deaths.
Furthermore it points out that the essential number is the stopping distance not the velocity of impact or the mass of the plane and contents.
Note also that basically g measures the acceleration, not the force (although they are related).
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LVL 25

Author Comment

ID: 38729463
Elsewhere I read where 1G to 9G's in one second was fatal.
But, that was not stated in the context of a 250,000 pound airliner falling out of the sky.
Swiss Air did not break up in the air. It appears to have broken up at impact. So, free fall maybe with engines running from 10,000 feet.
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But, I think people have said a penny dropped off the Empire State Building has the same force on the top of my head as a 2000 pound car falling off the same building.
Air resistance makes a coin fall no faster and with no more force at impact than a chicken feather. I think that is what people have said in response to a question about a penny off the top of the building would kill you if it hit you in the head.
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LVL 27

Expert Comment

ID: 38729820
"But, I think people have said a penny dropped off the Empire State Building has the same force on the top of my head as a 2000 pound car falling off the same building.
Air resistance makes a coin fall no faster and with no more force at impact than a chicken feather. I think that is what people have said in response to a question about a penny off the top of the building would kill you if it hit you in the head. "
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Unfortunately "people" are often wrong. In this case they certainly are.
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LVL 27

Expert Comment

ID: 38729823
Use common sense. If you were to stand under the Empire State Building would you rather be hit by a feather or a car?
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Author Comment

ID: 38730092
The pennies "reach terminal velocity and no matter how high we put the balloon, they never picked up any more speed." Terminal velocity is the maximum speed a falling object reaches and is determined by the object's weight and air resistance. Because a penny is lightweight and not aerodynamic, air resistance slows it down so much that its terminal velocity is quite slow.

But not so for many other objects, Bloomfield warns. "Even if they're relatively small, if they're aerodynamically streamlined -- like a ball point pen -- they'll reach the point at which they're going a couple hundred miles an hour, and that's dangerous," he said. "Don't dump your handbag out the top of a building. Something in that bag is likely to go awfully fast."

http://abcnews.go.com/2020/story?id=3131332&page=1

The Australian who jumped out of a space capsule a few weeks ago, reached over 700 miles per hour in his free fall, before he pulled the rip cord. And from the live TV his body was twisting the whole way down but he was conscious enough at 700+ mph to pull the cord. There was an auto rip cord as well.
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Author Closing Comment

ID: 38730103
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