Profound Query of the Day

A.N.Other said:
Rubbish tbh. How do you think stunts are done where people drop 20 or so floors. Stuntman jumps through sugarglass window and lands on a mahoosive bouncycastle-style-thingy. Another comparison is skydiving - you don't die when falling at terminal velocity, you release your chute, slowing you to almost nothing (in comparison, anyway). Bungee-jumping is the same.

If you had enough bubblewrap (a fair bit more than a metre or so I would have thought), you'd probably be fine, if a little shaken.
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The key word there being "mahoosive", which I'm assuming is derived from "massive". 1 metre of bubble wrap is nothing to the size of the giant inflatables stuntmen use.
 
I wouldnt want to fall more than 1 story wrapped in a meter of bubble wrap. As for 500ft? i think you'd stand a better chance unwrapping yourself on the way down and trying to fashion a bubble wrap parachute to reduce speed. It could be like a majic trick, give copperfield a bell.
 
What is it that makes this query so profound? :confused:

Back when I was at school my physics teacher reckoned that if you fall a great height, it isn't actually the impact that kills you, but what happens is the first time you hit, it breaks all your bones, and you bounce up, so when you come back down again, all the broken bones will damage your internal organs, so it is the second landing which does most damage. Could have been a load of rubbish though.
 
messiah khan said:
Its not the fall that kills you, its the rapid deceleration.
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Actually I read somewhere that most people that jump from great heights to their death tend to die during the fall of some sort of heart attack.

fini
 
Jotun said:
What is it that makes this query so profound? :confused:

Back when I was at school my physics teacher reckoned that if you fall a great height, it isn't actually the impact that kills you, but what happens is the first time you hit, it breaks all your bones, and you bounce up, so when you come back down again, all the broken bones will damage your internal organs, so it is the second landing which does most damage. Could have been a load of rubbish though.
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Hmmm im not sure the human body is bouncable :p maybe on grass lol but i doubt on anything solid lol, am i wrong anyone lol?
 
But your terminal velocity would'nt be the same as a normal body falling in freefall due to the extra air resistance so your terminal velocity will be less.

Edit: using the equation to work out terminal velocity and another website I think terminal velocity will be nearer 88Mph ("now Marty When it hits 88Mph..." :p )

http://en.wikipedia.org/wiki/Terminal_velocity
http://www.jayandwanda.com/tt/ballspeed_calc1.html

Vt = sqt [(2x150x9.8)/(1.2249x3.14x0.5)] = 39m/s (~88mph)

150kg being about right for a 70kg bloke with a **** load of bubble wrap round them! :p
1.2249 kg/m3 being the air density at 1m
3.14 being cross-sectional area
0.5 being drag coefficient of a sphere

Now just need to work out the Gforce for stopping at that speed through 1m. (I'm making the assumption that you will hit full Vt speed in 500ft, although I may see if that is true too)
 
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A.N.Other said:
Rubbish tbh. How do you think stunts are done where people drop 20 or so floors. Stuntman jumps through sugarglass window and lands on a mahoosive bouncycastle-style-thingy. Another comparison is skydiving - you don't die when falling at terminal velocity, you release your chute, slowing you to almost nothing (in comparison, anyway). Bungee-jumping is the same.

If you had enough bubblewrap (a fair bit more than a metre or so I would have thought), you'd probably be fine, if a little shaken.
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Stuntmen don't jump on to 'bouncy castle style' things. They jump on to giant air bags (for want of a better description), that have enough air in them to cushion the fall, but not enough to make it a rigid object.
Have you never seen them when they hit the bag? It rapidly sinks down to cushion the fall. A rigid object would seriously damage anyone.
Equally, stunts are sometimes performed into cardboard box towers, as they are again, enough to cushion the fall, but upon impact collapse.

Edit: Have you actually read whats been said so far, or read what you said? I can't believe you're at Oxford tbh.
 
Visage said:
Terminal velocity is about 120mph = 54 m/s

If you're surrounded by 1m of bubble wrap, you're decelrating from 54m/s to 0m/s in a space of 1m.

Thats a g force of about 145G.

You'd die, badly.
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54m/s for a human or for everything?

Wouldn't all that wrap cause a lot of drag and lower the top speed?
 
The_blue said:
54m/s for a human or for everything?

Wouldn't all that wrap cause a lot of drag and lower the top speed?
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See my above post, 54m/s is for an average human.

Edit:

The bloke would reach terminal velocity within the distance he fell to, in fact within 300ft, so you have the same chance of surviving if you fell 300ft or 3000ft. :p

So I make the G-force of a bloke falling 500 ft in a 2m diameter bubble wrap ball as 77G. But that doesnt take into account the bubblewrap slowing him down when he hits the floor. I just used simple uvats to work the G out. Anyone know how to work G out with the bubblewarp taken into account?

In my opinion the bloke would survive if he was resonably lucky, although he may not be able to walk for some time. :p

EDIT2: Visage is almost right if the ball was 1m in diameter. So if depends if the OP meant a 1m ball of bubblewrap or a ball of bubblewrap with 1m of wrap each side.
 
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Visage said:
Terminal velocity is about 120mph = 54 m/s

If you're surrounded by 1m of bubble wrap, you're decelrating from 54m/s to 0m/s in a space of 1m.

Thats a g force of about 145G.

You'd die, badly.
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It depends how long the bubblewrap takes to compress...

If you draw a simple graph of v versus t, assuming constant decceleration, the gradient of the graph is the decceleration. I.e. If you say that you slow from 54ms^-1 to 0 in 1 second, you're experiencing a force of approximately 5.4G.

One second is quite a long time though, so perhaps a decceleration time of 0.1 seconds is more feasible/realistic with regards to foam or bubblewrap.
 
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daz said:
It depends how long the bubblewrap takes to compress...

If you draw a simple graph of v versus t, assuming constant decceleration, the gradient of the graph is the decceleration. I.e. If you say that you slow from 54ms^-1 to 0 in 1 second, you're experiencing a force of approximately 5.4G.

One second is quite a long time though, so perhaps a decceleration time of 0.1 seconds is more feasible/realistic with regards to foam or bubblewrap.
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Thats the thing, you cant work it out exactly unless you know the time taken to compress. You just gave me an idea, be back in a minute! :p
 
daz said:
It depends how long the bubblewrap takes to compress...
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In a sense, you're right, but if the wrap takes too long to compress you hit the ground ;)

The wrap has to stop you before it compresses to the point at which you hit the ground.....
 
daz said:
It depends how long the bubblewrap takes to compress...

If you draw a simple graph of v versus t, assuming constant decceleration, the gradient of the graph is the decceleration. I.e. If you say that you slow from 54ms^-1 to 0 in 1 second, you're experiencing a force of approximately 5.4G.

One second is quite a long time though, so perhaps a decceleration time of 0.1 seconds is more feasible/realistic with regards to foam or bubblewrap.
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Except that, for a body to decellerate from 54 m/s, under a force of 5.4G (~54N), it would travel a distance of 27 metres......putting you somewhat underneath the pavement.......
 
ElRazur said:
You clearly missed the good ones. Speaking of " :rolleyes: "...How about i get one more free? :rolleyes:

EDIT
Just take a look
http://forums.overclockers.co.uk/search.php?searchid=2187639

**Points and laugh** Haaa
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I'm not the one complaining about 'quality of threads affecting GD' and not practicing what he preaches though am I? :p

If it makes you happy, read this thread title as.. <sarcasm>Profound Query of the Day</sarcasm> But, no it's shot right over your head :)
 
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