Merged Freefall is not evidence for Controlled Demolition

LSSBB

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LSSBB
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I keep seeing 'freefall' tossed around as evidence for controlled demolition, in threads where it would be off topic to discuss. Well, here is a thread where you can discuss it.
I put it to any proponent of the Controlled Demolition theory for World Trade Center 7 (WTC7), that:

  1. There is no definitively sustained period where the exterior of WTC7 is seen to collapse AT freefall acceleration.
  2. Any period of freefall acceleration is not proof of controlled demolition.

The first item I say because of measurement uncertainty: you cannot say precisely what the acceleration is at any time. Since CD proponents say the building freely falling is evidence that all support is removed, since gravity is constant for this purpose, the acceleration would be constant, which cannot be claimed due to measurement error. For research material, search the femr2 video thread as a start.

The second item I say because force applied from the interior collapse is putting additional load on the exterior, so that when the exterior finally gives under the increased load, the resistance from the collapsing bottom of the exterior is balanced somewhat by the applied load from the interior. With those two forces acting in opposite directions plus the force of gravity, the result can be acceleration at or above that of gravity Graphically:

picture.php


Ok Truth seekers, time to put your money where your mouth is. Prove to the world that there was significant sustained freefall (right at the acceleration of gravity), or that periods of freefall cannot be explained by a collapse without demolitions.
 
I'd add that even if some sub-assembly of a collapsing building experienced actual free-fall (i.e. no other [significant] force acting on it other than gravity) at any sub-period of time, this still would not be proof of CD, as of course it is perfectly possible for any part of a building to detach from the rest of the building in the course of a building collapse and fall freely until it impacts something below.

The easiest example could be a single brick that breaks free from a crumbling wall.
The next easiest example could be a sheet of connected bricks, a wall panel, or something similar breaking free from the wall.
The next easiest example could be an assembly of wall panels breaking free from the rest of the wall as a unit.
The next easiest example could be the upper portion of a wall breaking free from both the lower part and the interior of the building.
Etc.

To disprove a global claim like "free-fall of a subassembly is (absolutely, always) proof for CD", it suffices to bring just one example where it isn't.
I gave four easy to grasp examples from easy-to-do thought experiments.
Concept disproven.
 
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Oystein said:
I'd add that even if some sub-assembly of a collapsing building experienced actual free-fall (i.e. no other [significant] force acting on it other than gravity) at any sub-period of time, this still would not be proof of CD, as of course it is perfectly possible for any part of a building to detach from the rest of the building in the course of a building and fall freely until it impacts something below.

The easiest example could be a single brick that breaks free from a crumbling wall.
The next easiest example could be a sheet of connected bricks, a wall panel, or something similar breaking free from the wall.
The next easiest example could be an assembly of wall panels breaking free from the rest of the wall as a unit.
The next easiest example could be the upper portion of a wall breaking free from both the lower part and the interior of the building.
Etc.

To disprove a global claim like "free-fall of a subassembly is (absolutely, always) proof for CD", it suffices to bring just one example where it isn't.
I gave four easy to grasp examples from easy-to-do thought experiments.
Concept disproven.
Click to expand...

Thanks, Oystein, good addition.
 
I have in the past asked that actual building collapse videos other that those of the WTC structures , be put through the same analysis and a comparison made. Compare partial or total collapse acellerations for known fire or earthquake induced collapses, as well as those in straight down controlled demolitions.
However it seems no truther is interested enough to go about proving that such statements as ' free fall=CD ' and prefer to simply put it forth as an unsubstantiated declaration.

I also appreciate the pointing out that if free fall is the result of a severing of lower columns through an eight storey section then the acelleration of the now detached upper portion of the building cannot exceed g. I have in the past asked several 911 conspiracy proponents to explain the over-g measurements. I have seen patently ridiculous claims of implosions sucking the structure down and equally implausible space-a-beam claims but so far no known physics to explain it. I suspect that the reason is that as soon as they introduce other factors along the line of that described in the OP they understand that their premise of freefall = CD collapses immediately.(pun intended)
 
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jaydeehess said:
I have in the past asked that actual building collapse videos other that those of the WTC structures , be put through the same analysis and a comparison made. Compare partial or total collapse acellerations for known fire or earthquake induced collapses, as well as those in straight down controlled demolitions.
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Problem is i don't beleive there are any examples outside of actual demolitions of steel framed skyscraper complete straight down collapse due to fire or earthquake. Partial yes, but how much of a partial collapse would be considered enough to compare? Or are we considering any building material and simply looking at timing?
 
lexicon008 said:
Problem is i don't beleive there are any examples outside of actual demolitions of steel framed skyscraper complete straight down collapse due to fire or earthquake. Partial yes, but how much of a partial collapse would be considered enough to compare? Or are we considering any building material and simply looking at timing?
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This is a good thing, actually. It means that engineers have done their job and it takes an historic event to compromise these structures. Makes me feel good.

Unless you don't think the events of 9/11 where historic (as told by the OS).
 
lexicon008 said:
Problem is i don't beleive there are any examples outside of actual demolitions of steel framed skyscraper complete straight down collapse due to fire or earthquake. Partial yes, but how much of a partial collapse would be considered enough to compare? Or are we considering any building material and simply looking at timing?
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We are only seeking to falsify the supposed axiom that freefall= CD and thus are only interested in timing of a collapse, thus partial collapses fit the bill. How much partial collapse you ask. I would say it would have to be more than half a dozen storeys coming down as a block even if it does not involve the full width or depth of the structure.
I will grant that earthquake collapse likely is not a good comparison as an obvious outside force is involved that generally acts perpendicular to gravity.
 
Of course one could require a greater match to 911 collapses such as global collapse. However if one needs that level of match, and I cannot envision why that would be to just illustrate the premise, then one should also match construction techniques. Thus we need collapses involving long span open floor concept structures.
 
jaydeehess said:
We are only seeking to falsify the supposed axiom that freefall= CD and thus are only interested in timing of a collapse, thus partial collapses fit the bill. How much partial collapse you ask. I would say it would have to be more than half a dozen storeys coming down as a block even if it does not involve the full width or depth of the structure.
I will grant that earthquake collapse likely is not a good comparison as an obvious outside force is involved that generally acts perpendicular to gravity.
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Well in my unlearned opinion the free fall = CD argument really fails almost immediately since just about every CD i've witnessed (and no i haven't actually timed them) does not allow for free fall in the truest sense. The columns are blown in a sequence and as a result there are almost always lateral restraints or intact verticle columns for a period of time.
This immediately leads to resistance and therefore lack of free fall in almost every case.
Now having said that, the wtc did not fall at free fall.
They fell close to (in the sense that they fell very fast for a resistant structure which for the most part a CD isn't as it has much of the structure removed or weakened prior to collapse initiation). They fell relatively symetrically (even though we can see they were assymetrically damaged). In a CD this symmetry is done by design not by random chance that all the piece fell into place properly (no pun intended).
So yes..the free fall = CD argument essentially fails. It is however pretty hard to not say that the collapses happened alot faster then one would expect from a resistant structure. This is what implies that there was some other forces involved..one of which could have been CD.
 
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jaydeehess said:
Of course one could require a greater match to 911 collapses such as global collapse. However if one needs that level of match, and I cannot envision why that would be to just illustrate the premise, then one should also match construction techniques. Thus we need collapses involving long span open floor concept structures.
Click to expand...

I don't think collapse comparisons are necessary or relevant, unless someone can show me why. This for all intents and purposes is a unique building construction with unique circumstances. No building like this has ever been subject to CD either. All that is necessary here is to show that free fall is evidence of controlled demolition.

The above freefall is a good point, although it has not been definitively shown to have occurred. There exists a significant probability that the exterior of wtc7 fell at over g, and that can be explained by interior collapse applying a load and cannot be explained by controlled demolition eliminating all support.
 
lexicon008 said:
Well in my unlearned opinion the free fall = CD argument really fails almost immediately since just about every CD i've witnessed (and no i haven't actually timed them) does not allow for free fall in the truest sense. The columns are blown in a sequence and as a result there are almost always lateral restraints or intact verticle columns for a period of time.
This immediately leads to resistance and therefore lack of free fall in almost every case.
Now having said that, the wtc did not fall at free fall.
They fell close to (in the sense that they fell very fast for a resistant structure which for the most part a CD isn't as it has much of the structure removed or weakened prior to collapse initiation). They fell relatively symetrically (even though we can see they were assymetrically damaged). In a CD this symmetry is done by design not by random chance that all the piece fell into place properly (no pun intended).
So yes..the free fall = CD argument essentially fails. It is however pretty hard to not say that the collapses happened alot faster then one would expect from a resistant structure. This is what implies that there was some other forces involved..one of which could have been CD.
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I disagree that it is hard to not say that the collapse happened faster than would be expected from a resistant structure, for the reason I gave in point 2: The interior collapse applies a load on the exterior of the building.
 
lexicon008 said:
Well in my unlearned opinion the free fall = CD argument really fails almost immediately since just about every CD i've witnessed (and no i haven't actually timed them) does not allow for free fall in the truest sense.
...
Now having said that, the wtc did not fall at free fall.
...
So yes..the free fall = CD argument essentially fails.
...
Click to expand...

But this is Gage's argument, it is supposedly supported by 1900+ architects and engineers, and yet you understand - correctly! - that it is an invalid argument!

What does that tell you about the reliability of the arguments pushed by leading proponents of 9/11 Truth?
 
Oystein said:
But this is Gage's argument, it is supposedly supported by 1900+ architects and engineers, and yet you understand - correctly! - that it is an invalid argument!

What does that tell you about the reliability of the arguments pushed by leading proponents of 9/11 Truth?
Click to expand...

That is only 1 part of the argument.
If it was the Column 79 of the argument then maybe the whole argument collapses ;P
 
LSSBB said:
I disagree that it is hard to not say that the collapse happened faster than would be expected from a resistant structure, for the reason I gave in point 2: The interior collapse applies a load on the exterior of the building.
Click to expand...

perhaps but in the case of 7 the interior collapsed laterally did it not (if your assuming the interior structure collapsed and left a hollow shell)? This would presumably lead to only the furthest side of the interior collapse having a load that could cause an over G pull. The side that had collapsed internally first did not start collapsing externally immediately. So how can we say that it was loaded and pulled down above G?
And this is not what NISTs computer model shows unless i'm missing something.
 
lexicon008 said:
That is only 1 part of the argument.
If it was the Column 79 of the argument then maybe the whole argument collapses ;P
Click to expand...

It's a pretty central argument - it really is their main pillar of the 7 debate!

But their other pillars also fail:

- They claim there was a "rapid onset" of the collapse - there wasn't
- They claim there were "sounds of explosions at ground floor – a second before the building's destruction" - not true, no comparison at all to real CDs
- They claim "Symmetrical structural failure" - that is an ill-defined term, and I say it's not true - WTC7 showed significant asymmetries
- They claim it fell "through the path of greatest resistance" - there is no evidence for this
- They claim that falling "through the path of greatest resistance" is a "characteristics of classic controlled demolition with explosives" - utter nonsense
- They claim that WTC7 dropped into ots footprint - it didn't
- They claim that dropping into footprint is a "characteristics of classic controlled demolition with explosives" - not true: many CDs fall outside of the footprint, non-CDs can fall into it

What a load of fail!
 
Oystein said:
But their other pillars also fail:

- They claim there was a "rapid onset" of the collapse - there wasn't

i guess that depends on your definition of rapid and when you feel the collapse started.

- They claim there were "sounds of explosions at ground floor – a second before the building's destruction" - not true, no comparison at all to real CDs

agreed, there is very little in terms of sound evidence..but..most CDs are not done on a complete in use structure. They remove much of the materials that could dampen sound such as drywall, roofing, carpeting, furniture etc. They have preweakened the walls and floors. But I admit this does tend to argue against CD since with no preweakenig you should really need more explosives..unless you preweaken with the thermite;)

- They claim "Symmetrical structural failure" - that is an ill-defined term

agreed


- They claim it fell "through the path of greatest resistance" - there is no evidence for this

well again that depends on your terminology here. They cannot really prove it was the path of greatest resistance since resistance of the structure was not measured at the time of collapse so yes they are technically wrong. I think the point here was that it is unusual for a structure such as this to collapse through itself and not tip over say.


- They claim that falling "through the path of greatest resistance" is a "characteristics of classic controlled demolition with explosives" - utter nonsense

again agreed, although CDs due tend to collapse more neatly then non CDs i think

- They claim that WTC7 dropped into ots footprint - it didn't

it was pretty damn close

- They claim that dropping into footprint is a "characteristics of classic controlled demolition with explosives" - not true: many CDs fall outside of the footprint, non-CDs can fall into it

agreed in essence but again you look at the statement too literally maybe?
Click to expand...
 
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lexicon008 said:
perhaps but in the case of 7 the interior collapsed laterally did it not (if your assuming the interior structure collapsed and left a hollow shell)? This would presumably lead to only the furthest side of the interior collapse having a load that could cause an over G pull. The side that had collapsed internally first did not start collapsing externally immediately. So how can we say that it was loaded and pulled down above G?
And this is not what NISTs computer model shows unless i'm missing something.
Click to expand...

I am not saying the shell was hollow, only that he interior collapse preceded the exterior. We also cannot see the interior of the collapse, so we cannot see the direction of the progression outward from column 79, and also one wall is, I believe, not visible. There can be multiple points of attachment where a load is being applied on all walls.
 
LSSBB said:
I am not saying the shell was hollow, only that he interior collapse preceded the exterior. We also cannot see the interior of the collapse, so we cannot see the direction of the progression outward from column 79, and also one wall is, I believe, not visible. There can be multiple points of attachment where a load is being applied on all walls.
Click to expand...

well there lies the problem..where were the points of attachment and how much were they affecting the collapse? You can't really prove that the above G pull was due to load if you can't prove that there was load and where it was to begin with.
The visual record shows a wave of collapses from left to right (on the video) in terms of the east penthouse collapse then we see windows breaking from left to right. I agree with you that this implies internal collapse of some sort but we cannot say for sure that those collapses had any >G affect on the structure as it collapsed since the outer facade fr the most part collapsed as a whole and not from left to right (based of course on what we can see).
 
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lexicon008 said:
well there lies the problem..where were the points of attachment and how much were they affecting the collapse? You can't really prove that the above G pull was due to load if you can't prove that there was load and where it was to begin with.
The visual record shows a wave of collapses from left to right (on the video) in terms of the east penthouse collapse then we see windows breaking from left to right. I agree with you that this implies internal collapse of some sort but we cannot say for sure that those collapses had any >G affect on the structure as it collapsed since the outer facade fr the most part collapsed as a whole and not from left to right (based of course on what we can see).
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I don't have to prove anything. The point is to prove that the observed behavior can only be explained by controlled demolition. If you cannot do that, then the observed behavior cannot be used as evidence of controlled demolition.
 
"I don't have to prove anything. The point is to prove that the observed behavior can only be explained by controlled demolition. "

you win..it can't

"If you cannot do that, then the observed behavior cannot be used as evidence of controlled demolition"

not entirely true. The behaviour can't ONLY be explained by CD, other things could cause it, but CD could certainly cause the behaviour and therefore the behaviour could be consistent with CD.
 
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Oystein said:
- They claim it fell "through the path of greatest resistance" - there is no evidence for this
Click to expand...
Not to mention there is no evidence that this has any physics meaning whatsoever. Defy any ct to find this phrase in a physics text. Anyone?

:boxedin:
 
sylvan8798 said:
Not to mention there is no evidence that this has any physics meaning whatsoever. Defy any ct to find this phrase in a physics text. Anyone?

:boxedin:
Click to expand...

quite true..probably using the more dumbed down version so the common guy might understand it. If you start going into principles of least action and such then most people nod off.
 
lexicon008 said:
"I don't have to prove anything. The point is to prove that the observed behavior can only be explained by controlled demolition. "

you win..it can't

"If you cannot do that, then the observed behavior cannot be used as evidence of controlled demolition"

not entirely true. The behaviour can't ONLY be explained by CD, other things could cause it, but CD could certainly cause the behaviour and therefore the behaviour could be consistent with CD.
Click to expand...

If the observed behavior can be explained by CD and by not-CD, it is not evidence for CD. If it can be explained by not-CD and by CD, it is not evidence for not-CD. I am not claiming the observed evidence as evidence for not-CD, I am discounting it as evidence for CD above any other alternative.
 
LSSBB said:
If the observed behavior can be explained by CD and by not-CD, it is not evidence for CD. If it can be explained by not-CD and by CD, it is not evidence for not-CD. I am not claiming the observed evidence as evidence for not-CD, I am discounting it as evidence for CD above any other alternative.
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There is a thing in forensics called equivocal evidence... evidence that supports more than one theory.

since the behaviour in question can be explained by both cd and non-cd it is equivocal and can't be used to rule in or out the other theory by itself.

but i digress..i agree that free fall = CD is not supported.
 
lexicon008 said:
There is a thing in forensics called equivocal evidence... evidence that supports more than one theory.

since the behaviour in question can be explained by both cd and non-cd it is equivocal and can't be used to rule in or out the other theory by itself.

but i digress..i agree that free fall = CD is not supported.
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thumbup.gif
 
lexicon008, it is a refreshing change to encounter a poster here who at least sympathizes with, or assigns a significant likelihood to, 9/11 "Truth" claims of CD and who is able to hold differentiated views on single topics, agreeing with counterclaims when those seem well supported.
Thanks for that.

lexicon008 said:
i guess that depends on your definition of rapid and when you feel the collapse started.
Click to expand...
Correct. What Gage really is writing about it the collapse of the north wall, which, I'd agree, started to collapse "rapidly" - its roof edge went from rest[*] to around g within about a second.

But this was obviosly preceded by several seconds of gradual collapse progression, from the columns underneath the east penthouse, progressing west.

[*] Note: Femr2, who probably has done the most accurate measurement of the movement of the WTC7 northwall, and also some features of the twins (far superior to the work of Chandler or NIST) detected an instability more than a minute before the east penthouse fell, which showed itself in an oszillation which wasn't there before. This is in line with the even earlier observations of FDNY members that the building was moving.

lexicon008 said:
agreed, there is very little in terms of sound evidence..but..most CDs are not done on a complete in use structure. They remove much of the materials that could dampen sound such as drywall, roofing, carpeting, furniture etc. They have preweakened the walls and floors. But I admit this does tend to argue against CD since with no preweakenig you should really need more explosives..unless you preweaken with the thermite;)
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All agreed.
And there is no evidence for the presence, let alone use, of thermite (thermite is my pet topic here, I can teach you all about it, particularly why the red-gray chips cannot possibly be "thermitic", but that would derail this thread).

lexicon008 said:
agreed
Click to expand...
Thx.

lexicon008 said:
well again that depends on your terminology here. They cannot really prove it was the path of greatest resistance since resistance of the structure was not measured at the time of collapse so yes they are technically wrong. I think the point here was that it is unusual for a structure such as this to collapse through itself and not tip over say.
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It's pretty sad when a group that pretends to be of technical professionals doesn't define its terms, wouldn't you say?

The idea that the towers ought to have tipped over is really very silly and unbecoming of engineers or architects. Tipping over would mean that the center of gravity of the top part of a tower would have to be shifted by 100-200 feet within a very short time (less than, say, 5 seconds). Where so you imagine the momentum for such a move could come from? This would have to get offset by an equal but opposite momentum imparted in the lower part. This is Wiley Coyote physics - has nothing to do with reality.

All it takes for the north wall to descent essentially in free fall is for columns connections to disjoin on roughly one level and shift laterally by the with of one column (14 inches or whatever) - and that is what almost certainly happened. The wall can then descend more or less vertically (subject to the pushing and pulling from still-connected floors).

lexicon008 said:
again agreed, although CDs due tend to collapse more neatly then non CDs i think
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Possibly, probably, but there doesn't really exist any body of references of non-CD highrise collapses.

lexicon008 said:
it was pretty damn close
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Nope. Do you know that part of the north wall, which supposedly fell oh so neatly, actually fell across the street and on top (on the roof) of another highrise there, damaging that other building so severely it had to be demolished in turn? Debris from WTC7 also crossed the street to the west, slamming high into the Verizon building and contributing to the Verizon's >1 billion damage bill.
This is pretty damned different from "into the footprint" and a major deception (lie), in my opinion. You can't possibly say "into foot print" or even "pretty damn close to footprint", if you destroy and majorly damage buildings on the other side of at least two streets!

agreed in essence but again you look at the statement too literally maybe? [/QUOTE]
Maybe we really should expect a group of architects and engineers - professionals in technical, objective disciplines - to be very literal when making technical claims about an objectivily describable technical event?



But back to the point I made:

You had previously agreed that the "freefall" argument isn't valid, and I had asked you what you make of the fact that Gage and, supposedly, his 1900+ A&E, push that argument anyway. You handwaved this question, saying it's just one argument, and perhaps not central.

Now you agree that several other of the arguments Gage and his supposed 1900+ make about WTC are also invalid, or at least weak or ill-defined.

Is it maybe time for you to step back and assume that Gage does not present good arguments for a CD of WTC7 - period? And if he doesn't - who else does? Do any good arguments exist - at all?

I think not.
 
lexicon008 said:
Problem is i don't beleive there are any examples outside of actual demolitions of steel framed skyscraper complete straight down collapse due to fire or earthquake. Partial yes, but how much of a partial collapse would be considered enough to compare? Or are we considering any building material and simply looking at timing?
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It is pointless to compare them. No other building that ever collapsed partially or completely was built in any way like the towers or #7.
 
Oystein said:
"The idea that the towers ought to have tipped over is really very silly and unbecoming of engineers or architects. Tipping over would mean that the center of gravity of the top part of a tower would have to be shifted by 100-200 feet within a very short time (less than, say, 5 seconds). Where so you imagine the momentum for such a move could come from? This would have to get offset by an equal but opposite momentum imparted in the lower part. This is Wiley Coyote physics - has nothing to do with reality.

All it takes for the north wall to descent essentially in free fall is for columns connections to disjoin on roughly one level and shift laterally by the with of one column (14 inches or whatever) - and that is what almost certainly happened. The wall can then descend more or less vertically (subject to the pushing and pulling from still-connected floors)."
Click to expand...

All it takes?

All that pushing and pulling must have occurred extremely fast.

So fast in fact that all the WTC7's vertical supports amazingly cooperated in a synchronous, and instantaneous failure over multiple floors.

It was dropping like a tree felled with one swipe.

The WTC7 7 floor drop in 9 video frames = 3/10 of a second.

MM
 
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Miragememories said:
All it takes?

All that pushing and pulling must have occurred extremely fast.

So fast in fact that all the WTC7's vertical supports amazingly cooperated in a synchronous, and instantaneous failure over multiple floors.
...
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Wasn't instantaneous, as you well know. Fast yes, instantaneous no.
There was a transition period of close to a second, preceded by several seconds of internal collapse that compromised lateral bracing.

Absolutely sufficient for progressive (non-instantaneous) collapse. As you very well know, load redistribution occurs at the speed of sound in the material, which os very very fast for steel.

Please indicate that you understand that the equivalant-to-g acceleration of a part of the building for a part of the time did NOT come about "instantaneously" but gradually. You have seen femr2's (and David Chandler's) acceleration graphs, haven't you? Do any of them show a discontinuity, where a increases from 0 (or some value much <g) to g in an instant, i.e. delta-t = 0? Of course not - as you perfectly well know already.


So why do you litter this thread with a disproven lie? I have asked you so many times to stop lying. Will you ever?
 
Miragememories said:
All it takes?

All that pushing and pulling must have occurred extremely fast.

So fast in fact that all the WTC7's vertical supports amazingly cooperated in a synchronous, and instantaneous failure over multiple floors.

It was dropping like a tree felled with one swipe.

................................

The WTC7 7 floor drop in 9 video frames = 3/10 of a second.

MM
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The WTC7 north perimeter wall corner began the fall at less than FFA as the perimeter columns resisted and buckled, then the splices failed, then the wall with no support fell ~ FFA. Chandler ignores his own data for this < FFA period because he doesn't know engineering.

BasqueArch said:
NIST before Chandler
The upper 18 stories took 40 percent longer to fall than free fall time.

NIST after Chandler
The upper 18 stories took 40 percent longer to fall than free fall time.
-------------------------------------------------------------------------------

NIST NCSTAR 1-9 Vol2 for Public Comment (Draft Aug 2008)
SUMMARY OF FINDINGS
“Thus, the actual time for the upper 18 stories to collapse, based on video evidence, was approximately 40 percent longer than the computed free fall time and was consistent with physical principles. “
http://www.nist.gov/customcf/get_pdf.cfm?pub_id=909257


NIST WTC7 FINAL - 1A Report (Final November 2008)
SUMMARY
"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."
http://www.nist.gov/customcf/get_pdf.cfm?pub_id=861610


The lower columns buckled and at a small angle the splices failed, then the building fell with no resistance.
It is at this point, after the outside walls were collapsing, that Chandler claims the bombs went off. At all the exterior columns. There was no need.

Exterior columns shown buckled, failed splices.

fig-7-7.jpg



NIST’s velocity graph showing first stage of less than FFA. (Downward velocity shown as positive.)
freefall.jpg


Chandler’s velocity graph showing NIST’s first stage of less than FFA. (Downward velocity shown as negative)
WTC7-VideoAnalysis.jpg

NIST before Chandler
The upper 18 stories took 40 percent longer to fall than free fall time.

NIST after Chandler
The upper 18 stories took 40 percent longer to fall than free fall time.

Lower columns buckle, column splices fail, building wall falls unresisted at FFA. Chandler's silent bombs go off too late, they should have gone off before the building began to fall.
Click to expand...

 
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let the wise Dr. Shyam Sunder tell us the dillio:

"Well...um...the...first of all gravity...um...gravity is the loading function that applies to the structure...um...at...um...applies....to every body...every...uh...on...all bodies on...ah...on...um... this particular...on this planet not just...um...uh...in ground zero...um...the...uh...the analysis shows a difference in time between a free fall time, a free fall time would be an object that has no...uh... structural components below it. And if you look at the analysis of the video it shows that the time it takes for the...17...uh...for the roof line of the video to collapse down the 17 floors that you can actually see in the video below which you can't see anything in the video is about...uh... 3.9 seconds. What the analysis shows...and...uh...the structural analysis shows, the collapse analysis shows that same time that it took for the structural model to come down from the roof line all the way for those 17 floors to disappear is...um... 5.4 seconds. It's...uh..., about one point...uh...five seconds or roughly 40% more time for that free fall to happen. And that is not at all unusual because there was structural resistance that was provided in this particular case. And you had...you had a sequence of structural failures that had to take place and everything was not instantaneous."
--------

Note that:
--He acknowledges that freefall can only occur if there is no structure under the falling section of the building.
--He acknowledges that their structural modeling predicts a fall slower than freefall.
--He acknowledges that there was structural resistance in this particular case.
--He acknowledges that there was a sequence of failures that had to take place and that this process was not instantaneous.

Thus, he acknowledges that their model is at variance with the observable fact that freefall actually occurred. Their response is to hold to their model, deny that freefall occurred, and put up a smokescreen of irrelevant measurements that obscure the reality.

http://911blogger.com/node/17685
 
Freefall is not evidence for CD.

But my post count now reaching 15 is evidence I can post links.
 
cmckay said:
lol

Left picture: East penthouse intact.
Right picture: East penthouse gone, perimeter falling.

You realize there is several seconds between these pictures?
Click to expand...

Good catch :D

You need to realize that MM hardly ever composes a post without serious errors of fact (I suspect they are very often not merely errors; but in this case may well be)
 
Senenmut said:
...
Note that:
--He acknowledges that freefall can only occur if there is no structure under the falling section of the building.
--He acknowledges that their structural modeling predicts a fall slower than freefall.
--He acknowledges that there was structural resistance in this particular case.
--He acknowledges that there was a sequence of failures that had to take place and that this process was not instantaneous.

Thus, he acknowledges that their model is at variance with the observable fact that freefall actually occurred.
...
Click to expand...

Except he doesn't. All four points are fully in agreement with observed reality:
- He compares models to the behaivious he describes, i.e. average acceleration over several seconds - both align sufficiently
- Of course there was structural resistance - since acceleration was well under for most of the fall as well as on average
- The failure was indeed not instantaneous, as acceleration increased gradually from 0 to about g over a serious span of time.
- Once this period of progressive failure of vertical supports lower in the north wall had practically finished, there was no, or negligible, net resistance from that sub-assembly
 
Wow free fall. Is that a joke.


The idiocy is that there was so little resistance. Most of each tower was pristine and supposedly undamaged.
 
I guess some whiz could provide a free fall time vs the actual collapse time for each of the three WTC buildings.
 
Senenmut said:
let the wise Dr. Shyam Sunder tell us the dillio:

"Well...um...the...first of all gravity...um...gravity is the loading function that applies to the structure...um...at...um...applies....to every body...every...uh...on...all bodies on...ah...on...um... this particular...on this planet not just...um...uh...in ground zero...um...the...uh...the analysis shows a difference in time between a free fall time, a free fall time would be an object that has no...uh... structural components below it. And if you look at the analysis of the video it shows that the time it takes for the...17...uh...for the roof line of the video to collapse down the 17 floors that you can actually see in the video below which you can't see anything in the video is about...uh... 3.9 seconds. What the analysis shows...and...uh...the structural analysis shows, the collapse analysis shows that same time that it took for the structural model to come down from the roof line all the way for those 17 floors to disappear is...um... 5.4 seconds. It's...uh..., about one point...uh...five seconds or roughly 40% more time for that free fall to happen. And that is not at all unusual because there was structural resistance that was provided in this particular case. And you had...you had a sequence of structural failures that had to take place and everything was not instantaneous."
--------

Note that:
--He acknowledges that freefall can only occur if there is no structure under the falling section of the building.
--He acknowledges that their structural modeling predicts a fall slower than freefall.
--He acknowledges that there was structural resistance in this particular case.
--He acknowledges that there was a sequence of failures that had to take place and that this process was not instantaneous.

Thus, he acknowledges that their model is at variance with the observable fact that freefall actually occurred. Their response is to hold to their model, deny that freefall occurred, and put up a smokescreen of irrelevant measurements that obscure the reality.

http://911blogger.com/node/17685
Click to expand...

I am not looking for an analysis of someone else's analysis in the this OP, Senenmut. I am looking for how free fall could be evidence of CD. Free fall did possibly occur, it took time to build up to it if it did, and freefall was possibly even exceeded. It was not demonstrably constant free fall. I have shown that a load from the interior collapse can also result in free fall. Free fall is thus not evidence of CD any more than it is evidence of no-CD.
 
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