The Collapse Of WTC7: Why was it so fast?

[Aemilius]

swansont "Actually it's physics, and it's the same argument you make: that you don't get free-fall if you are colliding with material, but you will get free-fall if you don't."

 

I disagree. How can it be the same argument I'm making when I haven't made any argument? In other words, I haven't advanced any theory or made any argument, claim or assertion, I've only written a brief description that echoes the well known conditions under which free fall occurs....

 

"....gravitational acceleration only occurs when an object falls un-obstructed under the influence of gravity alone. If there's anything beneath the falling object that would tend to impede it's downward progress, then some of its gravitational potential energy will be used in overcoming the resistance and it will not be found falling at gravitational acceleration compared to an identical object falling un-obstructed from the same height at the same time over the same distance...."

 

....accompanied by an example animation illustrating the required conditions and expected results....

 

....along with another example animation that just illustrates why a difference in fall times can be expected between a free falling object (right) and another identical object (left) that encounters resistance, in this case a frangible impedance scenario....

 

Control on the right, details....

http://picasion.com/pic76/ef2992a1bed34a1ad9d2e8f520c5ad7e.gif

I thought I made it pretty clear in post 21 that my goal was to agreeably define free fall before continuing, I don't think I missed anything (open to correction)....

 

Does anyone disagree with the definition* of gravitational acceleration as presented here before we continue?

 

*The Imperial System of measurement used can easily be converted to any system one wishes.... it won't change the outcome.

Edited February 23, 2014 by Aemilius

[Ringer]

It should be noted that my comment was before the comment before it was edited, it was only the first schematic and the comment above it.

 

No, the schematic isn't an argument, it just illustrates free fall. How could a schematic be an argument? I'm just curious really, I don't have an argument/theory per se.... and the imperial system was good enough for the NIST to use in it's analysis and final report.

So what's your opinion of the whole thing Ringer? Do you agree with the NIST that the failure of one column caused/triggered the global collapse?

 

 

Yes, I know what free-fall is and that is why I asked if the schematic was your argument, it's a known concept and it didn't add anything to the discussion. I haven't read the analysis and final report in any sort of detail so I can't comment on what happened to the building. But what I have seen and read (about 9/11 conspiracies as a whole) there doesn't seem to be any credible evidence to support the controlled demolition angle.

[swansont]

swansont "Actually it's physics, and it's the same argument you make: that you don't get free-fall if you are colliding with material, but you will get free-fall if you don't."

 

I disagree. How can it be the same argument I'm making when I haven't made any argument? In other words, I haven't advanced any theory or made any argument, claim or assertion, I've only written a brief description that echoes the well known conditions under which free fall occurs....

 

OK, so it wasn't an argument, it was a reminder. (You were saying something about semantics, as I recall? )

 

 

The point still holds: you get freefall when there are no obstructions.

[Aemilius]

So we agree on the conditions required for free fall.

 

And I haven't seen anyone dispute the formal analysis of the event....

 

....carried out by the NIST that determined free fall descent occurred for 2.25 seconds, or approximately 105 feet....

 

....in "Stage 2" of the graph accompanying the final report....

 

....so I'll assume we can also agree on that.

Edited February 25, 2014 by Aemilius

[Ophiolite]

So, can someone explain to a simple minded geologist why the details of the mechanics of the collapse that meant that for 2.5 seconds there were no obstructions to the fall.

 

I am not a conspiracy theorist. I am reasonably confident a sound explanation exists. I just think it would be good to be able to read that explanation here. Will anyone oblige?

[Strange]

I think it was approximately in free fall (1) and that implies that there were no significant obstructions. A not terribly interesting factoid.

 

(1) Does anyone know the error bars on this estimate? It might be on that graph but it is illegible.

[John Cuthber]

So we agree on the conditions required for free fall.

 

And I haven't seen anyone dispute the formal analysis of the event....

 

....carried out by the NIST that determined free fall descent occurred for 2.25 seconds, or approximately 105 feet....

 

....in "Stage 2" of the graph accompanying the final report....

 

....so I'll assume we can also agree on that.

 

Was stage 1 the bit where the internal structure failed?

If so that would explain why there's roughly free fall in stage 2.

Of course, it also suggests that no explosives or anything like that were required.

And it's consistent with what the report cited very early in this thread says

'NIST NCSTAR 1A, WTC Investigation' said

The observed descent time of the upper 18 stories of the north face of WTC 7 (the floors clearly visible in the video evidence) was 40 percent greater than the computed free fall time. A more detailed analysis of the descent of the north face found three stages: (1) a slow descent with acceleration less than that of gravity that corresponded to the buckling of the exterior columns at the lower floors, (2) a freefall descent over approximately eight stories at gravitational acceleration for approximately 2.25 s, and (3) a decreasing acceleration as the north face encountered resistance from the structure below.

 

 

Why do you focus on those 2 seconds or so, and ignore the 1st 2 seconds?

Edited February 25, 2014 by John Cuthber

[Ringer]

Looking at the graph it seems that right when stage 2 occurs there is a drop in velocity. This would be consistent with the idea that the top structure met some sort of resistance (supporting beams and such) and broke through until it met other set of structural supports. It should also be noted that we are only looking at the north face of the building. It is possible that internally or another side of the building was falling before the North face, causing the North face to fall faster due to the structural support being damaged before that side met it. This is supported when looking at the picture and seeing the structure jutting from the top of the building falling before the north face falls.

Edited February 25, 2014 by Ringer

[swansont]

The issue that gets glossed over is the bald assertion that freefall is impossible without explosives. Not just unlikely. Impossible.

[John Cuthber]

The other issue that gets glossed over is that they didn't exhibit free fall.

"The observed descent time of the upper 18 stories of the north face of WTC 7 (the floors clearly visible in the video evidence) was 40 percent greater than the computed free fall time."

 

This whole thread is like a discussion of how Stalin was assassinated in 1943.

[Ringer]

Obviously the demolition was done using gravity manipulation

[Delta1212]

This whole thread is like a discussion of how Stalin was assassinated in 1943.

I'm pretty sure George W Bush was behind that.

[Aemilius]

Though the possible composition and placement of the explosives can still be debated, the fact that they were indeed composed and placed cannot.

 

Newtonian physical principles haven't changed. It's physically impossible for the lower part of the asymmetrically damaged building (three core columns and nine perimeter columns) to have progressively/naturally collapsed in any way that could result in the upper part of the building symmetrically descending straight down through itself (starting with column 79, circled below), through the path of greatest resistance, at anything near gravitational acceleration for any period of time....

 

 

 

 

....and there is absolutely no mode or combination of modes of progressive/natural structural failure driven solely by gravity that can ever give rise to the conditions required (below) for free fall to have occurred at any point during its descent....

 

 

 

 

....and anyone who believes otherwise (below) belongs in a lunatic asylum....

 

 

 

 

There is simply no point during a natural progressive gravity driven collapse of a steel frame skyscraper like this where one could say....

 

"Hold it.... right there! That's the point where all the steel columns and structural

components that were supporting the building just a moment ago (with an area

greater than that of a football field) will undoubtedly be found to be behaving in a

manner very much like air (below left).... so much so that it will take very careful

calculation to tell the fall times apart during this period of the

ongoing progressive structural failure (below right)"....

 

 

How could anyone who made it through high school really believe that it's not only possible but probable that the lower asymmetrically damaged part of the building progressively/naturally collapsed in a way that resulted in the upper part of the building actually accelerating as it descended symmetrically straight down through itself, through the path of greatest resistance (below right), and also, incredibly, that driven on solely by gravity it actually continued to accelerate so nearly to gravitational acceleration (below left) as to require very careful calculation for any difference between the two to be detected....

 

 

 

 

So far, the explosion model (below) is still the only one....

 

 

 

 

....that can realistically match and empirically be expected to create the conditions (below) that we know must have existed....

 

 

 

 

....beneath the literally falling visible upper part of the building (below) during its observed largely symmetrical descent at gravitational acceleration for approximately 105 feet in 2.25 seconds....

 

 

 

 

The undisputed confirmed observation of a significant period of gravitational acceleration....

 

 

 

 

....means an explosion or other type of event must have occurred that was powerful enough to quickly remove the support from beneath the upper part of the building (below right), either all at once or incrementally in advance of its descent, permitting it to descend at gravitational acceleration for the observed period and under the conditions required (below left) for free fall to occur....

 

 

 

 

After well over a decade, still, no other empirically verifiable explanation has been advanced. The building was brought down by means of explosives.... that's just the way it is.

 

Interesting that another post, firmly based on well known physical principles, immediately gets a "Neg Rep" in a science forum!

Edited August 26, 2014 by Aemilius

[arc]

Aemilius;

 

Insulting paragraph removed

Airliners can't stay in the air when they sustain catastrophic structural failure and neither can a building. Bridges have a history of collapsing, even without a preceding event initiating the failure.

 

Here is a list of bridge failures. Knock yourself out.

 

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

 

You could turn every one of them into a conspiracy, and sadly someone like you surely did after each tragedy.

Edited August 26, 2014 by hypervalent_iodine

[John Cuthber]

Aemilius,
You seem to have missed this, so I will repeat it for you.

The other issue that gets glossed over is that they didn't exhibit free fall.
"The observed descent time of the upper 18 stories of the north face of WTC 7 (the floors clearly visible in the video evidence) was 40 percent greater than the computed free fall time."

This whole thread is like a discussion of how Stalin was assassinated in 1943.

[hypervalent_iodine]

!

Moderator Note

arc,

The paragraph of insulting, derogatory remarks towards Aemilius are totally unacceptable. If you have nothing constructive to say, please don't bother contributing.

Aemilius: the same applies to you. If you cannot make a post without resorting to the rhetoric that anyone that may disagree with you lacks proper education and belongs in an insane asylum, it might be worth questioning whether or not you have a valid point at all.

[arc]

My sincere apologies for breaking the forum rules in this matter but I have seen the impact these people have on the families and more importantly the children of the victims of this tragedy. They can't even visit the site without risk of seeing or hearing these individuals. They are cruel to these families in the most stupid and misguided way.

[Aemilius]

Moderator comment acknowledged.

[andrewcellini]

starting from false premises leads to false conclusions is what i've learned today.

[imatfaal]

starting from false premises leads to false conclusions is what i've learned today.

 

Not necessarily - false premises would normally mean that any conclusion which the argument reaches cannot be relied upon and no truth value can be imputed. It is possible that the correct answer has been found by chance

 

But the general thrust of your post is completely agreed. Especially in this particular case

[John Cuthber]

Moderator comment acknowledged.

That's good.

Now, would you like to acknowledge my point.

Here it is again, in case you missed it.

The other issue that gets glossed over is that they didn't exhibit free fall.

"The observed descent time of the upper 18 stories of the north face of WTC 7 (the floors clearly visible in the video evidence) was 40 percent greater than the computed free fall time."

This whole thread is like a discussion of how Stalin was assassinated in 1943.

[Aemilius]

My sincere apologies for breaking the forum rules in this matter but I have seen the impact these people have on the families and more importantly the children of the victims of this tragedy. They can't even visit the site without risk of seeing or hearing these individuals. They are cruel to these families in the most stupid and misguided way.

 

Planes falling from the sky, old bridges collapsing without warning, the impact on families, weeping little children, cruelty, misguided stupidity.... Was there an on topic comment in there somewhere?

 

Nothing you've said empirically contradicts Post 38,... explosives brought down the building.

Edited August 27, 2014 by Aemilius

[Ophiolite]

Nothing you've said empirically contradicts Post 38,... explosives brought down the building.

This is completely true..........in a world where a biased agenda carries more weight than basic physics, or the evidence.

[Aemilius]

starting from false premises leads to false conclusions is what i've learned today.

 

Saying it is one thing, empirically demonstrating what you're saying is another. You haven't shown that any aspect of post 38 starts from a false premise, nor have you shown how or why the conclusion arrived at is based on a false premise.... unless you can empirically attack post 38 you're just wasting your time.

Not necessarily - false premises would normally mean that any conclusion which the argument reaches cannot be relied upon and no truth value can be imputed. It is possible that the correct answer has been found by chance

 

But the general thrust of your post is completely agreed. Especially in this particular case

 

You say you agree with the "general thrust" of andrewcellini's post,,,, What "general thrust"? Since nothing of Post 38 is specifically contradicted empirically by andrewcellini.... What precisely is it you "especially" agree with in this "particular" case?

 

You can all continue talking about false premises and false conclusions, airplanes falling from the sky, bridges collapsing without warning, weeping little children and impacted families, cruelty, misguided stupidity, the phase of the moon and whatever else, but the fact remains (no matter how many times you "Neg Rep" my posts) that no false premise, no false conclusion or any other error has been pointed out in post 38. The simple fundamental physical principles governing this scenario are clear (and have been for several centuries).

That's good.

Now, would you like to acknowledge my point.

Here it is again, in case you missed it.

The other issue that gets glossed over is that they didn't exhibit free fall.

"The observed descent time of the upper 18 stories of the north face of WTC 7 (the floors clearly visible in the video evidence) was 40 percent greater than the computed free fall time."

 

 

 

What's to acknowledge? The building verifiably dropped like a stone at gravitational acceleration for 2.25 seconds (approximately 105 feet).... that's a fact. Trying to sandwich a period of free fall as a "Stage" between two other less than free fall "Stages" to get a fall time that doesn't "exhibit free fall" is the very definition of absurd.

 

Does that mean that starting with Stage One of the complete collapse of a 110 foot tall bulding where it takes 5.71 seconds to descend one inch, followed by Stage Two where it descends at gravitational acceleration for 2.25 seconds (approximately 105 feet), and ending with Stage Three where it descends one inch in 10.28 seconds that it didn't "exhibit free fall" because the total fall time for the 110 foot tall building was 18.24 seconds?

 

Preposterous.

 

Post 38 remains empirically unassailed.... explosives brought down the building.

Edited August 27, 2014 by Aemilius

[Strange]

Nothing you've said empirically contradicts Post 38,... explosives brought down the building.

 

You have shown to be wrong in both your facts and your reasoning multiple times by multiple people. <shrug> The fact you choose to ignore it says more about you than any science.