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I challenge NIST Answers to FAQ - Supplement (December 14, 2007)

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posted on Feb, 26 2008 @ 11:09 PM
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Originally posted by Whodunnit
I can't believe that anyone still thinks that there were massive explosions. The planes hit with an equivalent of something like 2000 lbs of tnt. Any explosion that would have registered on a seismograph would have to be that large, and it would have been inescapable and undeniable.


It isn't that simple. The total energy may be equivalent, but only a fraction of that is going towards vibrating the massive steel columns all the way into the foundations, and then propagating seismic waves from there of the given magnitudes. That's what the seismographs were measuring, and not all the rest of the energy that was involved with the impacts (the kinetic energy severing and damaging columns, the fuel-rich fireballs, etc.).




posted on Feb, 27 2008 @ 12:29 PM
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Originally posted by bsbray11
It isn't that simple. The total energy may be equivalent, but only a fraction of that is going towards vibrating the massive steel columns all the way into the foundations, and then propagating seismic waves from there of the given magnitudes. That's what the seismographs were measuring, and not all the rest of the energy that was involved with the impacts (the kinetic energy severing and damaging columns, the fuel-rich fireballs, etc.).


You have a good point. But I wonder how accurate this is. Granted, you have roughly 900' of steel to disperse the energy before it gets to the bedrock, but you also have what is essentially a 900' lever arm that may be amplifying the shocks. Something to ponder.

Also, it doesn't adress the fact that 2's core never fell.



posted on Feb, 27 2008 @ 04:54 PM
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Whodunnit : I can't believe that anyone still thinks that there were massive explosions. The planes hit with an equivalent of something like 2000 lbs of tnt. Any explosion that would have registered on a seismograph would have to be that large, and it would have been inescapable and undeniable. Water helps, but it doesn't result in 100% of the energy being directed into the columns. Unless it's very deep water.

LT : That's why it's so difficult to answer time and time again the same questions. The questioner doesn't read all offered links to posts and threads.
In that case he would have had all his answers already on a plate.
Or he doesn't comprehend what's being explained.

I told and proved before in my original StudyOf9/11 thread, all 3 pre-collapse explosions were equivalent to the 2 plane IMPACTS.
And I gave the re-scaled seismic graphs for the WTC 1 and 2 tower collapses so you could at last SEE those identical pre-collapse spikes, comparable with the plane-impact spikes.
What more evidence do you want?
Especially the WTC 7 collapse spikes evidence is the most convincing, since the pre-collapse spikes were taller than the following total global collapse spikes. And these pre-collapse spikes, I REPEAT, were comparable to the 2 plane impact "EXPLOSIONS", which were of course a combination of impact at the 2 steel constructions and a fuel-air explosion of the remaining 2 jet fuel loads of each impact.


Whodunnit : So how much flooding was there? How much could there be? The basements were an acre on each floor. To get even 1 foot of water on 1 floor would require 325,000 gallons. Divide that by 60 min/hr and you get 5500 gal/min. That would take a pipe around 18 inches and under pressure to achieve that flow rate. And that's for just 1 floor. Of course, the water mains were cut too when 2 fell, so no more water for 1's collapse.

LT : That's why we become so desperate at times, having to see that most readers can't or won't really read all posts, or i.o.w. can't comprehend what is explained.

I addressed this already many times, with links to NIST reports about the flooding of parts of the basements, and the breaking of one huge water supply mains pipe already directly after the first plane IMPACT (which is highly suspicious in my eyes, I think it was blown, perhaps even just before, to hinder all NYFD efforts).

Can you imagine how much water flooded those basements after that shearing off of that huge pipe in the huge concrete bathtub wall which kept the Hudson water out?
And then I have explained multiple times that I am talking about the ELEVATOR shafts ends flooding first of course, because that were the deepest points to flood first, that's where the water will collect at first.
And even after that shafts end flooding, water kept coming, and inundated floors in the basements several inches deep, to foots deep. See the NIST reports.
There are also NIST witness reports of the floors above the atriums, flooded with inches of water from huge water tanks ruptured at above floors.
What caused these ruptures was not addressed.
But it facilitated the flooding of all elevator shaft ends, throughout the whole building. As you should know by now from studying all NIST reports, there were multiple elevator shaft ends, up both towers, the elevators were spaced apart in three factions towards the top, to facilitate a lighter construction, and it took care of fire security rules implemented. the top of each elevator shaft was sealed, to halt fluids to jump the shafts downwards or smoke upwards.
A whole NIST report is dedicated to explain all the elevator shafts features.


Whodunnit : Plus there's the problem with the fact that 2's core never failed. In fact, there were survivors of the collapse in there.

LT : As far as I remember, the surviving party was located in the tower's corner elevator shaft end at atrium level, which was the only part of it made of reinforced concrete. It was the group of people with the Korean named policeman in it.

But I never meant to say that the core failed totally from the basement level up.
I strongly suspect the real big explosives to have been situated at the first mechanical floors, just above the atriums. The basement explosions were just meant to assist in replacement laterally of the biggest core columns, to start the initial collapse sequence of the core column packets.

And I'm still not certain about the real reason for deep basement explosives, it could have been mainly for clearing the way for the following collapse-debris pile to be able to fill these basements.

Strong proof for these thoughts are the huge chunks of single atrium columns still standing after both tower collapses. The outer wall columns were not severed under the triple to massive single column joints at the top of the atrium level.



Whodunnit : While I believe a limited amount of explosives were used to initiate the collapse, what followed was unaided. there were no massive explosions 'ejecting' facades or whatever. That's just disinfo.

LT : then you obviously missed the videos I posted in these seismic threads where you can clearly see blast fronts on all 4 sides racing down the facades.
If you want to interpret these as compressed air from a gravity driven collapse of floors, its your choice.
However the amount of air expelled is three times bigger than the total normal volume of air per floor.
This has been measured by the volume of smoke and dust expelled.
That can only be achieved by excessive heating, instantaneously, of the available amount of air per floor, by explosive force.
EDIT to add source :
www.abovetopsecret.com...

If "they" would have initiated only the collapses, then how is it possible that the following racing down of the collapse fronts were so fast? Not hindered at the least by the still standing massive building under it.
You can plot the times for the first trajectories of the demolition, and compare that length of building mass to a purely gravity driven collapse time for that same trajectory, considering all resistance factors of that building we know of.
They will not match. At all.
The pure gravity driven collapse, if at all possible btw, will be much slower for that first trajectory which could be easily seen in multiple videos, in contrast to the rest of the downward trajectories, which were all blurred from view by the massive smoke and dust clouds.

"They" had to "guide" the collapse to the bottom, since they didn't want a tip-over collapse, like a tree trunk cut at its foot, and then toppling over.


EDIT to add to answer your last post :
LT : LDEO and NIST both stated that the recorded seismic effect of the plane impacts were in fact a very small part of the initial plane impact energy. That can be read in LDEO's dr. Kim's first posted report on the 9/11 events in November 2001. Link is in my threads.

[edit on 27/2/08 by LaBTop]



posted on Feb, 27 2008 @ 05:46 PM
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reply to post by LaBTop
 


The off handed remarks about my not reading your other posts, etc aren't necessary and border on inflammatory. I'm on your side of the fence on the entire issue, but just don't agree with your posts in the slightest. I read them. I disagree. Get over it.

Your entire theory rests on a precise timeline, but there's a lot of grey area there. It's impossible to come to a positive conclusion about what happened and when it happened when the times can't be pinned down with a reasonable degree of accuracy that your findings require. A proclamation from the morons at NIST about what happened and when is a poor start to base your findings on. You have a theory. It can't be supported to the degree that you would like it to using NIST. Sorry, but that's just the way it is.

One thing to think about. You stated that the structure under the collapse zone offered no resistance at all to the collapse. Free fall from that height is 9 seconds. The collapse took 14-16 seconds. To slow the collapse down that much required a HUGE amount of resistance. It's just that it wasn't enough to stop it. These are facts, something you should acquaint yourself with before you start spewing disinfo like this. It sets a bad example.



posted on Feb, 27 2008 @ 06:04 PM
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I disagree totally with you. You will get over that too.
I feel no need to spend more time on your arguments, so don't expect any more answers.



posted on Feb, 28 2008 @ 11:21 AM
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I will add a link to this post of mine in another thread to this thread, for cross linking- and historical reasons :
www.abovetopsecret.com...

It shows the strange complicity of high officials who want to comply to the available official theory.
And it shows that :
"""Even the smallest of those detonations (from the May 23rd demolition of the REMAINS of the Murrah building) had a larger effect on the seismic recording than the collapse of the building," he added, "which demonstrates that the explosives are much more efficient at exciting the ground motion than is the collapse of three-fourths of the building.""

Read there, my comments on the above.



posted on Feb, 28 2008 @ 12:30 PM
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Originally posted by Whodunnit
You have a good point. But I wonder how accurate this is. Granted, you have roughly 900' of steel to disperse the energy before it gets to the bedrock, but you also have what is essentially a 900' lever arm that may be amplifying the shocks.


So where is this 900' lever pivoting from and in what footage can I see the towers jiggling around from that point as the planes hit them? Why wouldn't anything in between snap first, before you got huge displacements on the far end of the lever?

It would also have to be doing this in a repetitive and extremely rapid motion to produce the given seismic waves.

I would just consider all the steel that was there to disperse the energy. It was there, and that's what it did. The towers would not have made very good tuning forks.



posted on Feb, 28 2008 @ 12:45 PM
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Originally posted by bsbray11

Originally posted by Whodunnit
You have a good point. But I wonder how accurate this is. Granted, you have roughly 900' of steel to disperse the energy before it gets to the bedrock, but you also have what is essentially a 900' lever arm that may be amplifying the shocks.


So where is this 900' lever pivoting from and in what footage can I see the towers jiggling around from that point as the planes hit them? Why wouldn't anything in between snap first, before you got huge displacements on the far end of the lever?

It would also have to be doing this in a repetitive and extremely rapid motion to produce the given seismic waves.

I would just consider all the steel that was there to disperse the energy. It was there, and that's what it did. The towers would not have made very good tuning forks.


900' from the points of impact to the ground.

Why would the motion be visible? Did we see the towers jiggling after the planes' impacts, and that was how the energy was transmitted into the ground? Nope. Your question was a Strawman.

You have no evidence to state that the towers would not have made good tuning forks. I say this cuz Willie Rodriguez, etc have stated that they heard the impacts, etc. Which is obviously false. They heard the ringing in the steel from the impacts. And the fuel explosions.

Anyways, these are just thoughts. Cool?



posted on Feb, 28 2008 @ 12:51 PM
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Originally posted by LaBTop
I will add a link to this post of mine in another thread to this thread, for cross linking- and historical reasons :
www.abovetopsecret.com...

It shows the strange complicity of high officials who want to comply to the available official theory.
And it shows that :
"""Even the smallest of those detonations (from the May 23rd demolition of the REMAINS of the Murrah building) had a larger effect on the seismic recording than the collapse of the building," he added, "which demonstrates that the explosives are much more efficient at exciting the ground motion than is the collapse of three-fourths of the building.""

Read there, my comments on the above.


So are you saying that since explosives are more efficent..... that this proves that there were no explosives used to bring down the towers, since in your "proofs" the part of the seismographs that you have indicated point to the use of explosives have SMALLER excursions?

This would be correct, if this is what you're saying....



posted on Feb, 28 2008 @ 01:06 PM
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Originally posted by Whodunnit
900' from the points of impact to the ground.


Ok, so the buildings are equivalent to lever arms from these points down? Where do they rotate? I'm not seeing it.


Why would the motion be visible?


Because to even move a millimeter at the ground, something higher up is going to move substantially by comparison. This is how a lever arm works.

Everything here is "just thoughts." Some make more sense, some less.



posted on Feb, 28 2008 @ 01:25 PM
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Actually, going by the lever arm theory, wouldn't the plane impacts be tremendously bigger than a directed bomb near the bottom of the tower?

Going by moments that is.

Moment equals force times moment arm (lever distance).

Let's say the force of the plane and the explosive force are equal for this example and equal 1 lbf. to make this easy.

The force of the plane times the moment arm of 900' would give us a moment of 900 ft-lbs.

The same force on the lower column (say 10 ft. from the ground) would give us a moment of 10 ft-lbs.

A very significant difference.

We would need a force of 90 times the plane impacts to see the same moment produced in this example.

So, how do we explain siezmic activity that is on par with the plane crashes? That's one hell of a force comming from somewhere IMO.



posted on Feb, 28 2008 @ 02:58 PM
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Whodunnit : So are you saying that since explosives are more efficient..... that this proves that there were no explosives used to bring down the towers, since in your "proofs" the part of the seismographs that you have indicated point to the use of explosives have SMALLER excursions?

This would be correct, if this is what you're saying....


LT : My thesis starts with proof of a lot of extra energy introduced before the collapse of WTC 7, you talk up there ONLY about WTC 1 and 2.

And that WTC 7 seismic chart has a bigger pre-collapse spike than the following global collapse.

You are correct in observing that WTC 1 and 2 have smaller pre-collapse spikes than the following global collapses. There's a reason for that.


Look at it this way for the reasons :

WTC 7 was a bottom-down demolition, where we saw all 4 building facades gliding down, essentially, without any big clouds spitting out sideways, most of the clouds spat out from the roof portion in the first few seconds.
Charges were obviously placed in the core columns, at the bottom of the cantilever construction above the ConEd station at floor 5, where most of them ended and leaned on.
That's why we saw nearly no clouds being expelled sideways, and the facades leaning inward while falling.
Classic bottom-down demolition, just one big group of explosives fired at once, perhaps a few cutter charges high up, and gravity does the rest.
Just like the Murrah building in Oklahoma City in 1995.
That's why we see one bigger pre-global collapse spike, followed by a smaller global collapse spike.
Because there was no need for more explosions, those were explicitly NOT wanted by the planners, or it would have been too damn obviously that WTC 7 was an artificial demolition, and not a gravity driven one !

Now it's just obvious, and a bit of rhetoric and lies still have some 30% of US citizens convinced that that smoothly sliding down of all 4 facades was a coincident by chance.
(Since this is the part of a populace which will f.ex. look at massive nuking of Iran, and then ask : Did we win? OK, let's go plant the flag in the front garden and pop a beer.)


WTC 1 and 2 were top-down demolitions, as planned following too quickly after the plane impacts.
Where we saw rolling clouds being expelled from all 4 building facades at impact floors, in a very fast downward movement.
Floors and adjacent facade parts were literally blown out in the first few seconds.
The planners obviously didn't have a lot of trust in a gravity driven further collapse, after first initiative explosions, so they created a rolling thunder of downward explosions, and told us that this is the normal collapse behaviour for such a high building. Pancaking. Bullocks!

And that's the main reason that we see in both WTC 1 and 2 demolitions, smaller spikes pre-run the global collapses spikes (but equally high as the WTC 7 pre-spikes).
Because the rest of their global collapses were one big EXPLOSIVE firework, which imprinted a much bigger spike on their collapse seismographs.
The WTC 1 and 2 pre-collapse bottom charges were tiny compared to the following freight train of top-down charges blowing up the rest of the buildings.



Conclusion:
If WTC 7 obviously was, and proved to be an artificial demolition, what more do I have to say?



posted on Feb, 28 2008 @ 03:36 PM
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Originally posted by Griff
Actually, going by the lever arm theory, wouldn't the plane impacts be tremendously bigger than a directed bomb near the bottom of the tower?

Going by moments that is.

Moment equals force times moment arm (lever distance).

Let's say the force of the plane and the explosive force are equal for this example and equal 1 lbf. to make this easy.

The force of the plane times the moment arm of 900' would give us a moment of 900 ft-lbs.

The same force on the lower column (say 10 ft. from the ground) would give us a moment of 10 ft-lbs.

A very significant difference.

We would need a force of 90 times the plane impacts to see the same moment produced in this example.

So, how do we explain siezmic activity that is on par with the plane crashes? That's one hell of a force comming from somewhere IMO.


Wouldn't a 1 ft-lb force at the end of a 900' lever give you 90 ft-lb at 10'?

1 ft-lb x (900'/10')=90lbs?

The movement, in inches, will be divided by 90. IOW, a 90" move at 900' will give a 1" move at 10'. But the force will be multiplied by 90, right?

This is what I've been thinking. Less movement but a lot of leverage to transmit force. And the plane impacts didn't produce any visible to the naked eye movement either, but it still produced an effect on the graph.

So using real world numbers, if we agree that the planes hit with the equivalent energy of 2000 lbs of tnt, wouldn't the 'bombs' have to be 90x bigger to reproduce the same effects? Because they didn't have any leverage advantage. That's a pretty big bomb, even if we assume that they would be 10x more efficent at putting their energy directly into the core columns. Which then brings up the question of how big the shape charges would have to be in order to cut through the 5" steel found in the cores near the bottom. Plus I believe they were covered in concrete, which means removing concrete, which presumably would have been noticed, OR need an even larger blast to cut through the steel AND concrete.

Also, I've been thinking about the speed of sound through steel. Isn't it like 10-15 times the speed of sound through air? I wonder what effect this would have on the energy transmitted. And whether or not it would amplify it.

When you ask "How do we explain...." I assume you mean the seismic activity during the collapse? I've always assumed that this is when the building was collapsing, but before the columns hit the ground. And then when the activity increases, that's where the first ext columns begin hitting the ground. The collpase front was at 60 mph+/-. The ext columns were faster, since they were in free fall. Maybe 90-100mph? How much energy would that give, if we assume a 50 ton column assembly?

What's the formula again? 1/2 mass x velocity?

Actually, I'm beginning to like your theory of thermite cutting the horizontal braces high up, which would allow easier buckling. Hmmmm.



posted on Feb, 28 2008 @ 03:52 PM
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This is the definitive scientific answer to all of the above "tuning-fork" impact energy thoughts and also answers one of your other questions.

www.ldeo.columbia.edu...

Page 2 of 9, Excerpt :
""Seismic signals from both impacts are characterized by relatively periodic motion and their spectra are above the noise only for frequencies from about 1.3 to 1.6 Hz. Those frequencies are more than 10 times the frequency of the lateral fundamental mode of each tower.""

Page 5 of 9, Excerpt :
""The seismic energy of a ML 0.7 to 0.9 computed for the impacts is a tiny fraction of the kinetic energy of each aircraft, about 2 x 10^9 J. That associated with the combustion of 50 to 100 tons of fuel in each aircraft is roughly 10^12 J, most of which was expended in the large fireballs (visible in TV images) and in subsequent burning that ignited material in each tower.
Less than a millionth of the fuel energy was converted to seismic waves.""



posted on Feb, 29 2008 @ 05:49 AM
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Originally posted by LaBTop
This is the definitive scientific answer to all of the above "tuning-fork" impact energy thoughts and also answers one of your other questions.

www.ldeo.columbia.edu...

Page 2 of 9, Excerpt :
""Seismic signals from both impacts are characterized by relatively periodic motion and their spectra are above the noise only for frequencies from about 1.3 to 1.6 Hz. Those frequencies are more than 10 times the frequency of the lateral fundamental mode of each tower.""

Page 5 of 9, Excerpt :
""The seismic energy of a ML 0.7 to 0.9 computed for the impacts is a tiny fraction of the kinetic energy of each aircraft, about 2 x 10^9 J. That associated with the combustion of 50 to 100 tons of fuel in each aircraft is roughly 10^12 J, most of which was expended in the large fireballs (visible in TV images) and in subsequent burning that ignited material in each tower.
Less than a millionth of the fuel energy was converted to seismic waves.""


Okay... a lot of crap to read to get to this point, and I have to say that I am not certain that you are talking about much, spare for the sake of talking to hear your brains rattle.

Anyway - the problem with seismic data is that it's inconsistent and omnidirectional. If two waves reach the same seismograph at the same time - it cannot differentiate between the two (only the use of multiple stations can determine that - and that area is not known for having an extensive array of seismographs available to facilitate accurate triangulation methods). Additionally, just as you have issues with density differential in water causing Sonar to behave in rather unpredictable manners (which is why people are still used as sonar techs - they can take into consideration extraneous factors that computers could never take into account). Currents, channels of warm water, rocky ocean floor instead of a more muddy floor, etc - all affect the behavior of Sonar.

Similarly, seismic waves are also affected. In the case of an Earthquake, it's like a Sonar array listening to the underwater detonation of a nuclear bomb - channels of warm water a few hundred meters across won't have much of a real effect in the end.

Even taking into account the collapse of the Twin Towers - you're talking the difference between a firecracker and a 500lb general purpose bomb between the collapse of the towers and an Earthquake. So even small factors (with respect to an Earthquake) can have some serious repercussions for the measurements. Sewer systems, atmospheric pressure, the amount of rainfall, etc - those will have an effect on the way the vibrations are transfered through the ground.

So, what am I getting at? It's rather simple. First off, you're dealing with a chaotic system and very minute measurements of energy using one source of data. Second off, the amount of energy required to make that spike noticed on the seismograph could NOT have been overlooked at ground zero. The amount of energy required to do that (placed into a bomb) would have leveled several city blocks. A physical impact to create such an impact tremor could possibly be caused by the debris hitting the ground (which would be supported by the diminishing energy leading out of the spike). And a direct strike to the structure required to generate that kind of read-out would have made the entire structure explode into dust in a mater of a few milliseconds.

That is, assuming some conduit didn't allow for better transfer of a certain frequency (much like a waveguide) and create a more efficient means of energy transfer - which would cause standard energy decay formulas to be rendered useless without direct knowledge of the conduit.

And, just as statistically likely, another event elsewhere (and much closer) to the seismograph could have been picked up simultaneously with the collapse of the towers.

And I'll see where this goes - I've been out of this debate for a while.



posted on Feb, 29 2008 @ 06:25 AM
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Originally posted by Whodunnit
Wouldn't a 1 ft-lb force at the end of a 900' lever give you 90 ft-lb at 10'?


Force is measured in lbs. When I used lbf. above for the force, it ment pounds force. Habit I guess from being an engineer. Because there is a difference between pounds force and pounds mass.

Anyway, if you are starting with ft-lb., you are starting with a moment.

To keep it as a force for now, we'll see what deflection would be.

deflection equals (Force/6EI)(2L^3-3L^2x+x^3)

Where L is the length of the cantilever and x is the point where the force is being applied. E is the elastic modulus and I the moment of inertia.

For simplicity (and that they would be the same for the most part because I is defined by the area and centroid of the member), let's say that I is also equal to 1 in.^4)

E would also be the same because it is steel, so let's simplify by using 1 psi.

I will do the calculations when I get to work. But, basically, I think I may have mislead you into thinking foot-pounds when I typed "lbf".



posted on Feb, 29 2008 @ 07:07 AM
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Oh for Pete's sake...

Force is measured in NEWTONS!!!! NEW-TONS! Named after the man who was one of the first to study and document the properties of gravity. *has a conniption fit* We use the metric system in Science and engineering - it's easier.

Anyway - one newton is equal to the force required to accelerate one kilogram at one meter/second/second.

As for your questions about levers and scales, balances, etc - it's a question of torque.

...Here...

Although I lost what you all were trying to prove with that point.

Sheemeny Christmas.... and you all want to try and debate that physics doesn't allow for the WTC to collapse like it did......... .... Tons of credibility to you, here



posted on Feb, 29 2008 @ 08:23 AM
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Originally posted by Aim64C
Oh for Pete's sake...

Force is measured in NEWTONS!!!! NEW-TONS! Named after the man who was one of the first to study and document the properties of gravity. *has a conniption fit* We use the metric system in Science and engineering - it's easier.


You are dead wrong. Here in the US, we use pounds force. Or where do you think psi comes from? That means pounds per inch squared. I thought you were an engineer?

Educate your self:

en.wikipedia.org...:Units_of_force


Anyway - one newton is equal to the force required to accelerate one kilogram at one meter/second/second.


And a pound force :


[edit] Use of pound as a unit of force

In some contexts, such as structural engineering applications, the term "pound" is used almost exclusively to refer to the unit of force and not the unit of mass. In those applications, the preferred unit of mass is the slug, i.e. lbf·s²/ft. In other contexts, the unit "pound" refers to a unit of mass. In circumstances where there may be ambiguity otherwise, the symbols "lbf" and "lbm" and the terms "pounds-force" and "pounds-mass" can be used to distinguish.

There are three common, equally valid ways of doing calculations with mass and force in the foot-pound-second (fps) systems (and other systems such as inch-pound-second systems not discussed here). These three ways are summarized in the table below, which also includes the corresponding metric units.


en.wikipedia.org...


As for your questions about levers and scales, balances, etc - it's a question of torque.


Torque is moment. I thought you would have learned that in engineering school?


Although I lost what you all were trying to prove with that point.


It's called deflection and moments and forces. To compare them from different points on a cantilever column. Again: Engineer?


Sheemeny Christmas.... and you all want to try and debate that physics doesn't allow for the WTC to collapse like it did......... .... Tons of credibility to you, here


What's that again about credibility? Maybe you should research before you jump on someone when you don't know what the hell you're talking about?

[edit on 2/29/2008 by Griff]

[edit on 2/29/2008 by Griff]



posted on Feb, 29 2008 @ 09:22 AM
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reply to post by Griff
 


Back to the deflection. I just realized that simplifying the E gives a huge deflection, so I'm going to use E for steel, which is: 29x10^6 psi.

Deflection for our 1 lb. of force. at 900 feet above the base would give us: 51,724 feet of deflection.

Obviously this does not amount to the real deflection because I assummed 1 for the force and 1 for the moment of inertia. To do an actual analysis, I would need to calculate "I" and use the actual force.

But, to compare it is enough.

Deflection for our 1 lb. force at 10 feet from the base would be: 316,807 feet of deflection.

So, going by deflection:

An equal force acting near the base would be more.

This says that if the siezmic energy is the same as the plane strikes just before collapse, you would only need an equivalent of the plane strikes of .163266 or 16.32 % of the force of the plane strikes.

So if the plane strikes were 2,000 lbs force of TNT. A force at the base to cause an equivalent deflection would be 326.532 lbs force of TNT.

If I have messed up on the calcs. Let me know. I rushed through the calcs. and I don't have my good calculator on me.



[edit on 2/29/2008 by Griff]



posted on Feb, 29 2008 @ 10:16 AM
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Um - no.

Force is, typically, measured in units as the SI standard. Grams (and more commonly Kilograms - since it's a unit we can comprehend much easier - much like the difference between pounds and ounces).

Additionally, the metric system is simply easier to work with and requires fewer conversions and makes errors in calculations less likely.

So, you "can" use pounds - but, operationally and when working the math, it's best to use the metric system. Convert it over after you've done all of the math so that those who are not familiar with the metric system can better understand if you need to - but I shifted over to the metric system a long time ago - you should, too.

And, as I said before, your issue is one of torque - as it is an expression of the amount of force being applied. Hang a weight on the end of a rod - and all of the forces experienced can be broken down into a function of torque.

Why? A load extended out from a focal point, perpendicular to gravitational attraction, blah blah - exacts a force on the focal point. Now, the amount of torque will change as the object drops, like a pendulum. But it works fine for figuring static loads - and you could easily graph the function of torque exacted on the fulcrum over a period of time.

We use something similar in electronics to calculate the various voltages and values in a circuit at any given point in time along an AC waveform. Adding multiple 'weights and levers' to the system, even at different angles and lengths is simple - everything will behave according to the same rules and all of the values will follow a sine function.

It's the same in dealing with AC waveforms that are not synchronized (or "out of phase") with each other - thus, you can calculate their values at any given point in a referenced waveform based on their phase angles (what you call a deflection angle), and determine the total net voltage (and current), and its direction (polarity).

Same concept - different application. After you've determined the net force at play, all you have left to do is compare it to the material's tolerances (although this is where the geometry of your material being subjected to the force and its relation to the direction(s) of that force come into play more than anything - and that's a whole different ballgame, static strengths of materials based on their geometry).

It's not about nomenclature - it's about knowing how things work. Half the time I can't tell you what, exactly, it is I'm solving for with the correct nomenclature. I simply know what relative value I need to have, and how to arrive at it, and how it relates to the rest of the system.

Anyone can regurgitate textbook jargon and be conditioned to use various formulas and nomenclatures when prompted to do so. It's an all together different ability to be able to be presented with a problem that you've never seen before, and never been instructed how to solve it - and be able to use your knowledge of other bits and pieces of how things work to arrive at a solution (and bonus points if it's the correct solution).

Which is why I have a 98 ASVAAB on record - I can freely and accurately apply various bits of information and knowledge I've accumulated along the way to solve very alien and abstract problems.

Don't try and learn formulas - it's a waste of time. Experience and learn principles so that you can 'feel' what is going to happen well before you do the math to prove it.

Anyway - just what are we trying to prove with various mathematical operations regarding extended loads? I lost track of who was debating what, why, and for what cause.






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