What is Free Fall?

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Offline Aemilius

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Re: What is free fall?
« Reply #100 on: 28/12/2013 09:34:24 »
So.... Was I mistaken?

....I've gone to a lot of trouble to explain how torsional stresses are incurred in a collapsing steel-and-concrete structure.

And I really just want to say, once again, how much I appreciate your patience and the time you've taken to discuss it with me.... I'm very glad to have met you.

There are, however, other features of the aerostatic model that I see as being possibly/probably problematic though, aside from the obvious fact that the actual conditions required for free fall are never created in the course of this model playing out....

The "piston" effect....

The West Penthouse breaks in half immediately upon beginning its descent. I believe this would have largely negated the piston effect that must be relied on to explain a catastrophic build up of aerostatic pressure since the "piston", right from the start, falls in at least two pieces, so there wouldn't have been any kind of a "seal" there between the "piston" and the "cylinder wall" to fascilitate any aerostatic build up of pressure, and in addition to that, further on, there would have been nothing to prevent any aerostatic build up that did occur from simply venting in an upward direction out through the gaping hole left in the roof of the building after/as the volume of rubble that had made up the West Penthouse continued its descent within the building.
 
The "bursting"....

After reviewing the video multiple times, the evidence for an "aerostatic blowout" or "bursting" event that you point to in the video emerging from the facade at the far end of the building about five stories beneath the West Penthouse, amazingly, actually appears at almost the exact same time as the beginning of the descent of the West Penthouse itself. I believe this could explain windows being blown out on one or maybe two floors immediately below the penthouse, but it doesn't seem at all probable at that point, after just the first few feet of its descent, that the West Penthouse could possibly have developed enough aerostatic pressure within the building to have blown out even one window five stories below, let alone the cladding, after having only fallen such a short distance prior to the appearance of the purported "bursting" five stories below.

The "shockwave"....

The evidence for the "shockwave" that's seen texturally rippling accross the buildings facade, as with the "bursting" event, amazingly, also appears at almost the exact same time as the beginning of the descent of the West Penthouse itself, and again, just as with the "bursting" but even more so, it doesn't seem at all probable that, at that point in its descent, it could possibly have developed anywhere near the level of aerostatic pressure within the building that would be required to generate such powerful and wide spread effects, racing throughout the building and buckling columns as it reverberated throughout the 610 foot tall structure that covered an area greater than that of a football field. Although the windows are seen to shatter in a way that's suggestive of a "shockwave", inexplicably, there is no visible indication of any accompanying ejecta similar to the "bursting" event, no papers, no smoke, no dust.... nothing. The windows merely shatter which, to me, is really much more suggestive of a slight structural flexure having occurred as a result of the first violent initial moments of descent of the West Penthouse as it tore itself away from other structural components, thereby distorting the normal dimensions of the window frames and causing the windows to shatter progressively in rapid succession across the facade of the building, a process that would, like the "shockwave", also have continued for the entirety of the buildings descent, or until all the windows shattered.

Thanks again for your time and all your responses Mr. Calverd.
« Last Edit: 28/12/2013 20:31:56 by Aemilius »

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Offline Aemilius

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Re: What is free fall?
« Reply #101 on: 28/12/2013 20:55:20 »
Just a note to add that those are all just subjective debatable observations. The main objection that thoroughly deflates the aerostatic model is still that it badly fails to display a close enough behavioural correspondence to the confirmed observation of gravitational acceleration, since there is no point at which the conditions required for it to occur actually arise in the model as it plays out to completion. We could revisit the rest if/when that hurdle is behind us.
« Last Edit: 28/12/2013 21:21:11 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #102 on: 29/12/2013 01:05:55 »
Remember that you don't need spectacular ejecta to weaken the structure. A few extra pounds internal pressure per square foot of cladding is all that is required to destroy the lateral and torsional stiffness of the building. And in a tall modern building the windows are a significant contributor to the stiffness of the structure. 

More importantly, the collapse of the west penthouse isn't the cause of the failure but an early visible effect. You stated that the primary cause was a fire some way below, which presumably weakened some of the steel uprights. Once the steel starts to buckle at one point, the weight of all the floors above it starts to move downwards and between them they create quite a substantial piston. One foot of collapse will increase the air pressure by about 1 lb/sq ft in the storey immediately below. The problem is that you can't see the internal floors moving. 

And finally, aerostatic blowout doesn't cause collapse by taking away all the supporting structure. All it does is reduce the stiffness of the building, which then accelerates as seen.

Quite clearly the conditions do arise for near-g acceleration, and there is no evidence for a magical dematerialisation of the internal structure, so if you don't like the obvious mechanism I proposed, you will have to propose a better one! What do you suggest?
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Offline Aemilius

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Re: What is free fall?
« Reply #103 on: 29/12/2013 02:01:00 »
Thank you Mr. Calverd, let me ruminate on all that for a bit. Before I forget though, just for the sake of clarity....

Was I mistaken or not (reply 99) as to what you originally constructed your theory/model around? 
« Last Edit: 29/12/2013 05:47:46 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #104 on: 29/12/2013 16:30:12 »
The key is in an earlier exchange, around 67 - 69, where I discussed the rigidity of a compound structure . A simple brick shed derives all its properties from the compressive strength of the brick shell, because there isn't anything else, so if you blow the bottom outwards it will collapse as a simple piston, but we are dealing here with multiple internal compartments and substantial intermediate loads in the form of concrete floors. The whole thing only works as a whole, so removing or weakening the exterior panels allows the stuff inside to collapse, particularly if the fire has been burning for long enough to weaken several interior uprights. The piston/blowout mechanism is the last straw that triggers the rapid phase of collapse, not the entire mechanism.
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Offline Aemilius

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Re: What is free fall?
« Reply #105 on: 31/12/2013 20:05:08 »
So to review your theory....

Column 79 buckles due to heat.

Five other columns that, along with column 79, had supported the West Penthouse then buckle in rapid succession.

The now unsupported West Penthouse, together with at least the five or so floors immediately below it, begins to descend as a substantial "piston" causing a catastrophic build up of aerostatic pressure within the building below (even though it immediately breaks in half leaving a gaping hole in the roof which appears in the video to actually be venting pressure upward through the top of the roof)....



At the same time as the West Penthouse is beginning to descend, it causes the roof to move, setting in motion a process that "progressively disintegrated" the support structure below (spontaneous catastrophic progressive structural disintegration.... a novel mode of structural failure?)....



Over the next four seconds or so the "piston", as it continues to descend, gives rise to multiple aerostatic blowouts (even though no multiple aerostatic blowouts are observed that indicate anything like that occurred) that further weaken the building by blowing out cladding and windows (even though no cladding or ejecta, spectacular or otherwise, are observed being blown out anywhere)....



During the same four or so seconds, as the penthouse descends, multiple structurally transmitted stresses (generated by multiple aerostatic blowouts there's no evidence of) invisibly reverberating throughout the steel structure at the speed of sound quickly causes more columns to begin buckling elsewhere within the building....



Together, this constellation of contributing factors consisting of a progressive sequence of progressive failures occurring at various times and in different ways throughout the building ultimately ended up coming together to act in concert at some point, miraculously causing the 610 foot tall building to literally fall (right) for over 100 feet at gravitational acceleration straight down through itself as if in air (left) through the path of greatest resistance....

 
To more easily explain the acceleration of the descending upper part of the building to near-free-fall (it was, after all, only essentially free fall, not free fall, and there was always some negligible resistance that must be taken into account), we need only reverse what we have known for centuries about what actually happens during a real natural progressive structural failure so that resistance to the descending upper part of the building gradually decreases rather than gradually increasing as it actually would (increasing resistance invariably causes the descending part of any naturally collapsing structure, aside from bridges and other structures that pass through the air, to either just come to a halt, or come to a halt and then topple)....

There's no need for even cursory scenarios, analogies or any diagrams that would even begin to show how any of this could possibly happen either, because this is simply how loaded minimally stiff structures behave under these conditions (even though no similar incidents of any kind are cited or referred to that would in any way suggest anything of the sort).

It's clear that the conditions for near free fall arose (all the while remaining perfectly unclear as to exactly how the conditions required for even near-free-fall could possibly arise), and since there's no evidence of any magical dematerialization of supporting structure that rematerialized on the other side of the moon, if I don't like the obvious mechanism your proposing (which couldn't be any less obvious) I'll just have to come up with something better.
   
As far as coming up with something better goes Mr. Calverd.... you already hit a home run man! And it didn't involve any magical dematerialization of supporting structure, nor did it require any machinations like those that have, of necessity, blossomed from the aerostatic model as it's evolved, attempting to explain something it can't possibly explain. The (when applied to the building) inherently miraculous aerostatic example of the "brick shed aerostatic blowout" absolutely fails to display even a tenuous behavioural correspondence with observations. Of the two examples you originally mentioned (gas explosion and aerostatic bursting), it's actually the extraordinarily simple gas explosion example of the brick shed you mentioned that superiorly displays an immediate and solid one to one behavioural correspondence with observations and accounts for the emergence at some point of the conditions required for free fall to arise. No miracle there.... good job!

When comparing the aerostatic model to the gas explosion model, unlike the Rube Goldberg aerostatic model, the gas explosion model easily replaces all of the above with a single sentence....

Judging by the confirmed observation of a significant period of gravitational acceleration, a high probabilty exists that a gas or other type of explosion or event must have occurred that was powerful enough to quickly remove the support from beneath the upper part of the building, either all at once or incrementally in advance of its descent (right), permitting it to descend at gravitational acceleration for the observed period of time and under the conditions required (left) for free fall to occur....


I think I'm done with the aerostatic model, but there is one thing I'm really curious about though. When you originally considered/came up with those two examples.... How did you manage the Olympically executed Herculean pole vault over Occams razor?

Can you try to delineate for me in a simple step-by-step way what the line of reasoning was that led you to choose the aerosatic model over the gas explosion model as being most probable (if you recall)?
 
« Last Edit: 06/12/2015 05:00:23 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #106 on: 31/12/2013 20:23:37 »
No.

You said the fire was some way down the building (8th floor?) so the movement of the west penthouse clearly isn't the first stage of collapse - it just happens to be the first externally visible sign. We have no idea of the state of the intermediate floors.

Had there been a gas explosion you would expect to see (a) the shockwave emanating from the level of the explosion, not from  near the top of the building (b) significant ejecta from that level and (c) not a lot of collapse since the steel frame would probably have withstood a contained burst at one level - more likely to have blown out the windows symmetrically without damaging the steelwork or breaching the floors.

Intentional explosive demolition is done by attaching simultaneous high-explosive charges (gas is not a high explosive) to the steelwork itself, to produce the kind of torsional failure that I think probably occured here. 

And remember that aerostatic blowout isn't the whole picture - it merely renders the structure "unstiff" and therefore unable to support torsional loads as the floors collapse.

I like the idea of polevaulting over Occam's razor. But given the starting conditions you offered, with no suggestion or evidence of a gas explosion, much less of a continuing fire during the descent, I wouldn't have used gas as the pole.

Quote
a process that "progressively disintegrated" the support structure below (spontaneous catastrophic progressive structural disintegration.... a novel mode of structural failure?).

That's what you can see on the video - at least the external evidence. Our task is to explain it.
« Last Edit: 31/12/2013 20:26:49 by alancalverd »
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Offline Aemilius

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Re: What is free fall?
« Reply #107 on: 31/12/2013 21:03:58 »
Thank you for that in depth analysis of why a gas explosion wouldn't bring down the building, but I didn't limit the cause of the explosion to gas alone, what I said was....


"....a high probabilty exists that a gas or other type of explosion or event must have occurred that was powerful enough to quickly remove the support from beneath the upper part of the building, either all at once or incrementally in advance of its descent...."
« Last Edit: 24/01/2014 14:20:45 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #108 on: 01/01/2014 11:38:19 »
As we discussed earlier, if you remove the support explosively, the upper stories will accelerate immediately at a rate close to g. They didn't.
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Offline Aemilius

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Re: What is free fall?
« Reply #109 on: 04/01/2014 18:15:22 »
Intentional explosive demolition is done by attaching simultaneous high-explosive charges (gas is not a high explosive) to the steelwork itself, to produce the kind of torsional failure that I think probably occured here.

No. Intentional explosive demolition is rarely done by attaching simultaneous high-explosive charges to the steelwork.... it's done by attaching precision timed high-explosive charges to the steelwork.
 
Quote
a process that "progressively disintegrated" the support structure below (spontaneous catastrophic progressive structural disintegration.... a novel mode of structural failure?).

That's what you can see on the video - at least the external evidence. Our task is to explain it.

Misplaced concreteness, Mr. Calverd?

As we discussed earlier, if you remove the support explosively, the upper stories will accelerate immediately at a rate close to g. They didn't.

And as I just pointed out, simultaneous detonation of the charges is rare. In fact, since the detonations can be (and routinely are) precisely timed, the door is thrown wide open for a variety of possible outcomes. One could quickly detonate all the charges at once for immediate acceleration to free fall, or one could detonate them slowly over time, including a period of free fall at any point one wished.... so that's not ruled out yet. 

To sum up....

My position is that not only is it impossible for the lower part of the building to have progressively/naturally collapsed in any way that could have resulted in the upper part of the building descending at anything near gravitational acceleration (below left) for any period of time during it's descent (below right), but also that there is absolutely no mode or combination of modes of progressive/natural structural failure driven solely by gravity that could ever give rise to the conditions required for anything near free fall to occur at any point during its descent....


Your position (unless I'm misunderstanding things incorrectly) is that not only is it somehow possible for the lower part of the building to have progressively/naturally collapsed in a way that would result in the upper part of the building accelerating as it descended (below right), but also that, driven solely by gravity, it would actually continue to accelerate so nearly to gravitational acceleration (below left) as to require careful calculation for any difference between the two to be detected....


I don't see how it can to do us any good to continue researching all the possible structural failure modes (or even make up new ones) in the hope of finding that special one that can create the conditions required for even near-free-fall to occur because it's physically impossible.

When it comes to your "catastrophic aerostatic blowout"....


...."speed of sound stress propagation shockwaves"....


...."spontaneous progressive structural disintegration" theory....


We'll just have to shake hands, agree to disagree.... and return to our respective universes.

P.S. - Diogenes, your posthumous guest and loyal eulogist, told me to tell you that.... "Though Perpetual Motion may be impossible, take heart, for the 'Oxford Bell' continues to ring!"
« Last Edit: 19/02/2016 08:58:40 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #110 on: 04/01/2014 23:50:41 »
'
Quote
I don't see how it can to do us any good to continue researching all the possible structural failure modes (or even make up new ones) in the hope of finding that special one that can create the conditions required for even near-free-fall to occur because it's physically impossible.

Suit yourself, but on my planet we assume that what we see and measure is indeed physically possible.

Never believe a philosopher - especially one that lives in a barrel. Trust your own eyes.
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Offline Aemilius

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Re: What is free fall?
« Reply #111 on: 05/01/2014 11:38:39 »
....on my planet we assume that what we see and measure is indeed physically possible.

Apparently you can see and measure things that aren't even there.... Must be some planet!

At almost the exact same time as the West Penthouse begins to break up and descend, there's evidence of venting five or so stories below it and out the top of the building above it as well.... but you see a massive multi-floor piston instantly causing a catastophic aerostatic blowout and powerful shockwave (all created by just the first few feet of the descent of the West Penthouse).
 
There's really nothing but a puff of smoke/dust at the first purported blowout.... but you see evidence of not just one but multiple aerostatic blowouts and shockwaves having occurred.

At almost the exact same time as the West Penthouse begins to descend, windows begin to shatter down and across the facade over multiple floors with no accompanying ejecta whatsoever, no smoke, no papers, no dust, nothing. Only a structural flexure can explain that (there was no pressure behind the windows).... but you see a powerful aerostatic shockwave racing accross the building through both walls and floors (all created by just the first few feet of the descent of the West Penthouse).

Though not one panel of cladding is seen to be dislodged during any of this.... you see evidence of multiple aerostatic blowouts having dislodged enough cladding/windows around the building to seriously affect its rigidity.

Though the entire facade of the building remains largely intact as it descends and there's no visible sign of any buckling or structural failure having been caused by the roof moving.... you actually see a mysterious new failure mode that can cause spontaneous widespread catastrophic progressive disintegration of steel columns.
 
Is there even one recorded incident of anything like this ever actually happenning that would tend to support your assertion about how the building came down?
« Last Edit: 05/01/2014 13:10:08 by Aemilius »

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Offline Aemilius

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Re: What is free fall?
« Reply #112 on: 05/01/2014 13:28:50 »
Interesting to note that I'm not getting slapped around (as I'm accustomed to), but neither is there any chorus of support for your explanation either Mr. Calverd. Even if one subtracts my 1,749 edits, there're still quite a few "views of the thread.... Where do the rest of you fall on this issue?
« Last Edit: 19/02/2016 09:06:50 by Aemilius »

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Offline Bored chemist

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Re: What is free fall?
« Reply #113 on: 05/01/2014 14:10:04 »
I can't speak for anyone else, but I didn't bother to get involved in this discussion because I got bored of refuting absurd claims about the tower falling years ago.

All the evidence supports Alan's point of view.

It fell down because some shits flew a plane full of jet fuel into it.
That fire heated the steelwork until it failed. The upper floors fell down and, since skyscrapers are not designed to take massive vertical shock loads, the rest collapsed.
It's not possible to analyse the video footage accurately enough to measure the acceleration to a high enough precision to rule out near free fall.
Typical video pictures are about 500 hundred lines high, and the image falls through about half the frame height so, at best you can measure the height of the building in each frame to about 1 part in 250.
That's simply not enough precision to rule out the suggestion that the building fell down.

You have, essentially, no evidence; but you have wasted 5 pages talking about it.

Anyone joining in with the discussion to point this out to you wouldn't have stopped you rambling on about it.
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Offline Aemilius

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Re: What is free fall?
« Reply #114 on: 05/01/2014 15:07:43 »
I can't speak for anyone else, but I didn't bother to get involved in this discussion because I got bored of refuting absurd claims about the tower falling years ago.

Well, like I said, I'm a relative newcomer to the internet so, sorry if it's already been exhaustively discussed. As far as absurd claims go, I haven't made any claims. So far we've just discussed Mr. Calverd's absurd claims.

All the evidence supports Alan's point of view.

And precisely what "evidence" is that Bored chemist?

It fell down because some shits flew a plane full of jet fuel into it.[

Indicating that you haven't a clue as to what Mr. Calverd and I have been discussing for the last 100 or more posts!

That fire heated the steelwork until it failed. The upper floors fell down and, since skyscrapers are not designed to take massive vertical shock loads, the rest collapsed.

Conclusively proving that you haven't a clue as to what Mr. Calverd and I have been discussing for the last 100 or more posts!

It's not possible to analyse the video footage accurately enough to measure the acceleration to a high enough precision to rule out near free fall.

Hah! Yeah, sure pal, everyone knows your assessment trumps the NIST.... Ridiculous! High enough precision to rule out near free fall?  What does that even mean?
 
Typical video pictures are about 500 hundred lines high, and the image falls through about half the frame height so, at best you can measure the height of the building in each frame to about 1 part in 250.

I'll get you the email address for the NIST. Why bother me with it? Take it up with them!

That's simply not enough precision to rule out the suggestion that the building fell down.

Not precise enough to rule out the suggestion that the building fell down? Hilarious! You're a riot man.... you're going to be bigger than Jerry Seinfeld! 

You have, essentially, no evidence; but you have wasted 5 pages talking about it.

I don't know about the five wasted pages bit, but somehow you've managed to squeeze a whole truckload of waste into just one post. Very impressive!  And when the hell did I ever say I had any "evidence" of anything? Got a quote.... Or would you like to just keep making it up as you go along?

Anyone joining in with the discussion to point this out to you wouldn't have stopped you rambling on about it.

Well, Bored chemist, I can say with confidence that your joining the discussion certainly didn't change a thing! Ask yourself this Einstein....

Why would a bunch of jibberish coming from someone who doesn't even know what the topic is change anything? Your whole post is a bunch of worthless crap!

If you're supposed to be the chorus of support for Mr. Calverd.... woe to Mr. Calverd.

« Last Edit: 19/02/2016 09:12:59 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #115 on: 05/01/2014 15:29:52 »
Quote
Though the entire facade of the building remains largely intact

A couple of inches is all it takes.

Anyway, enough of my hypotheses. What do you think happened?
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Offline Aemilius

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Re: What is free fall?
« Reply #116 on: 05/01/2014 15:34:05 »
Right, now it's a couple of inches, before it was a couple of feet.... C'mon!

What do I think happened? I'm nobody.... Who cares what I think? You're the Physicist, you're the one who's supposed to deliver scientific truth to me, not the other way around. I don't feel you're doing that (nothing personal).
« Last Edit: 28/01/2014 16:21:27 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #117 on: 05/01/2014 15:48:11 »
If we are being pernickety, it's Dr Calverd, if you don't mind.
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Offline Aemilius

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Re: What is free fall?
« Reply #118 on: 05/01/2014 15:49:58 »
You mean persnickety? Well we're not so it will remain Mr. Calverd, unless you really find it objectionable.... Would you prefer "Dr. Calverd" Mr. Calverd? From now on I'll refer to you as "Dr. Allen Caverd Ph.D. Physicist"
« Last Edit: 06/01/2014 00:12:17 by Aemilius »

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Offline Aemilius

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Re: What is free fall?
« Reply #119 on: 05/01/2014 17:05:46 »
Now that we've addressed all the etiquette issues Dr. Allen Calverd Ph.D. Physicist.... Was there any forthcoming response to reply 111?
« Last Edit: 08/01/2014 02:27:11 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #120 on: 05/01/2014 17:12:09 »
Alan
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Offline Aemilius

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Re: What is free fall?
« Reply #121 on: 05/01/2014 17:18:42 »
Right (terribly sorry), "Dr. Alan Calverd Ph.D Physicist".... got it. Was there an actual response to reply 111?
« Last Edit: 06/01/2014 00:09:59 by Aemilius »

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Offline alancalverd

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Re: What is free fall?
« Reply #122 on: 05/01/2014 17:26:29 »
#115, IIRC
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Offline Aemilius

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Re: What is free fall?
« Reply #123 on: 05/01/2014 17:53:46 »
So all of reply 111....

Apparently you can see and measure things that aren't even there.... Must be some planet!

At almost the exact same time as the West Penthouse begins to break up and descend, there's evidence of venting five or so stories below it and out the top of the building above it as well.... but you see a massive multi-floor piston instantly causing a catastophic aerostatic blowout and powerful shockwave (all created by just the first few feet of the descent of the West Penthouse).
 
There's really nothing but a puff of smoke/dust at the first purported blowout.... but you see evidence of not just one but multiple aerostatic blowouts and shockwaves having occurred.

At almost the exact same time as the West Penthouse begins to descend, windows begin to shatter down and across the facade over multiple floors with no accompanying ejecta whatsoever, no smoke, no papers, no dust, nothing. Only a structural flexure can explain that (there was no pressure behind the windows).... but you see a powerful aerostatic shockwave racing accross the building through both walls and floors (all created by just the first few feet of the descent of the West Penthouse).

Though not one panel of cladding is seen to be dislodged during any of this.... you see evidence of multiple aerostatic blowouts having dislodged enough cladding/windows around the building to seriously affect its rigidity.

Though the entire facade of the building remains largely intact as it descends and there's no visible sign of any buckling or structural failure having been caused by the roof moving.... you actually see a mysterious new failure mode that can cause spontaneous widespread catastrophic progressive disintegration of steel columns.
 
Is there even one recorded incident of anything like this ever actually happenning that would tend to support your assertion about how the building came down?

....is explained by reply 115....

A couple of inches is all it takes.

Oh man.... that's rich!
« Last Edit: 05/01/2014 17:56:41 by Aemilius »

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Offline Aemilius

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Re: What is free fall?
« Reply #124 on: 06/01/2014 01:07:05 »
I think it's been an interesting and informative conversation. I see your theory Dr. Calverd, and even though I believe I've shown it to be completely baseless and thoroughly disagree with it, it's your theory and you're welcome to it. I think I'll leave it at that and just read the opinions/theories of others (if any) and respond to those, as we've reached something of an impasse.

Thanks again sincerely for all your responses Dr. Calverd, looking forward to corresponding with you again.... maybe next time something a little less controversial. Thanks to everyone else that commented too (except you Bored chemist!). 
« Last Edit: 19/02/2016 09:19:24 by Aemilius »

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Offline Aemilius

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Re: What is free fall?
« Reply #125 on: 06/01/2014 17:47:47 »
....I got bored of refuting absurd claims about the tower falling years ago.

If your entrance is any example, you couldn't refute a fairy tale.


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Offline Aemilius

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Re: What is free fall?
« Reply #126 on: 09/01/2014 02:34:11 »
This was presented as an anonymous 47 story tall building so there wouldn't be any reason for any theory to fall into the category of "Not Allowed" or "Off Limits". All a theory has to do is be consistent with physical principles and display a solid behavioural correspondence (a predictable outcome similar to confirmed observations) in order not to be "ruled out" as a possible contender that explains the whole thing. It's not a whodunit, it's a howdidit. For the analysis it doesn't matter who the tenants may have been, why anyone might have done it, how they could have done it, whether anyone saw Bin Laden's face in the smoke or a lizard changing into George W. Bush, or even what the name of the building was or where it was located.... and it doesn't matter if "some shits" were flying around in planes full of jet fuel either.

My position hasn't changed....

It's physically impossible for the lower part of the building to have progressively/naturally collapsed (below) in any way that could result in the upper part of the building symmetrically descending straight down through itself, 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.....


 
So, Bored chemist, if you want to haul yourself aboard the sinking ship of Dr. Calverds theory and believe all the evidence supports his point of view, at what point during his theoretical post catastrophic aerostatic blowout/speed of sound stress propagation/spontaneous progressive structural disintegration collapse would you say....
 
"Hold it.... Right there! That's the point where all the columns
will undoubtedly be found behaving in a manner very
much like air (left).... it will take very careful calculation
to tell the fall times apart during this period of
the ongoing progressive structural failure (right)."


Dr. Calverds position is that not only is it possible but probable that the lower 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.


I don't really have a theory per se, but if I had to choose one, it would obviously have to be Dr. Calverds other model, the "explosion" model (below left) that was skipped over in favor of the "aerostatic" model (below right) because the explosion model, unlike the aerostatic model, can actually create the conditions required for free fall to occur (below center). The explosion model clearly shows an immediate and solid one to one behavioural correspondence with the confirmed observation of gravitational acceleration, and it can easily account for that at any point during the descent of the upper part of the building anytime one wishes.... in contrast to the fantastic catastrophic aerostatic blowout/speed of sound stress propagation/catastrophic spontaneous progressive disintegration invention that, oh yeah, leaves all the columns and support structure in place!


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


....that can realistically match and 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.


So the closest thing to a theory I have (and in answer to Dr. Calverds earlier question about what I think happenned), at least at this point, would go something like....

Judging by the confirmed observation of a significant period of gravitational acceleration, a high probabilty exists that 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.



« Last Edit: 03/05/2015 10:48:12 by Aemilius »

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Offline Bored chemist

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Re: What is free fall?
« Reply #127 on: 12/01/2014 13:13:31 »
....I got bored of refuting absurd claims about the tower falling years ago.

Care to show what's wrong with my assertion about the number of video lines, and the best available precision on the fall rate?
Please disregard all previous signatures.

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Offline alancalverd

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Re: What is free fall?
« Reply #128 on: 13/01/2014 11:50:59 »
OK, back in the swim.

Let's have an explosion. But it clearly (according to the NIST velocity graph) occured about 2 seconds after the west penthouse started moving so it wasn't the primary cause of collapse, nor did it cause much debris to be ejected. A very interesting scenario indeed. How was it orchestrated, and what explosive produces more suck than blow?
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Re: What is free fall?
« Reply #129 on: 13/01/2014 22:32:19 »
OK, back in the swim.

Thank God (figuratively speaking).
« Last Edit: 14/01/2014 10:21:00 by Aemilius »

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Offline JP

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Re: What is free fall?
« Reply #130 on: 16/01/2014 23:26:29 »
Calling other people's claims "worthless crap" is pushing the rule to "keep it friendly" on the forum.  Please try to stay civil in here.

Thanks,
The Mods

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Re: What is free fall?
« Reply #131 on: 21/01/2014 21:11:04 »
Hello JP (nice to meet you)....

I understand the "keep it friendly" rule JP, and I think the fact that the ongoing discussion between Dr. Calverd and I has been a perfectly civil and enjoyable exchange (even when mildly contentious) clearly demonstrates that. I'll not repeat what I said earlier, but neither will I take it back. When it comes to the insulting monument to irrelevance that is reply 113 though, let me ask you this....

How does one respond to an immediate and open display of hostility in a "friendly and civil" way? Between just which two blows of his broadsword did you expect me to reach out to this Bored chemist fellow?
« Last Edit: 28/04/2015 22:40:32 by Aemilius »

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Re: What is free fall?
« Reply #132 on: 21/01/2014 21:14:35 »
Hi Dr.Calverd....
 
Especially interested (actually dying) to read your take on all this.... Can you make sense of anything this Bored chemist fellow has written?
 
By the way, I'm looking forward to exploring the explosion model with you, but since we're sort of in between the "aerostatic" and "explosion" models, I think I'll take a bit of a break for a week or so. Just wanted you to know I haven't lost interest.

Take care.

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Re: What is free fall?
« Reply #133 on: 21/01/2014 21:16:12 »
Hey Bored chemist....

Look man, in spite of the Moderators admonition, I have to stand by my characterization of your reply 113....

I can't speak for anyone else, but I didn't bother to get involved in this discussion because I got bored of refuting absurd claims about the tower falling years ago.

All the evidence supports Alan's point of view.

It fell down because some shits flew a plane full of jet fuel into it.
That fire heated the steelwork until it failed. The upper floors fell down and, since skyscrapers are not designed to take massive vertical shock loads, the rest collapsed.
It's not possible to analyse the video footage accurately enough to measure the acceleration to a high enough precision to rule out near free fall.
Typical video pictures are about 500 hundred lines high, and the image falls through about half the frame height so, at best you can measure the height of the building in each frame to about 1 part in 250.
That's simply not enough precision to rule out the suggestion that the building fell down.

You have, essentially, no evidence; but you have wasted 5 pages talking about it.

Anyone joining in with the discussion to point this out to you wouldn't have stopped you rambling on about it.

I openly challenged you to back it up (using quotes/links/articles) or take it back and you've done neither. Instead, you now seem more interested in trying to take the helm and steer the focus of the thread to grilling me about why some aspect of your invisible plane full of jet fuel claim/assertion won't work, and now you're even trying to imply an appeal to authority on my part for citing NIST data, ostensibly in support of some imaginary claim you think I've made....  I've advanced no theory, nor have I made any claims or assertions of any kind.
 
Why are you demanding answers to questions from the anonymous eighth grade dropout questioner instead of just asking Dr. Calverd, a recognized bona fide veteran research Physicist eminently qualified to answer them? As anyone can see, you're just not making any sense!

I don't have any academic credibility and I didn't come here to give answers, I came here to get answers from the brighter lights here. I didn't set out to see you in a negative light either, but until you address/account for what you wrote in reply 113, I have no choice....

At this point you've proven nothing, you've backed up nothing, you've taken back nothing, you've refuted nothing, your invisble fuel laden plane theory (if that's what it is) makes no sense and your focus on me instead of the topic is just odd.... I honestly can't see where you've really said anything at all!

In view of all that and pending some sort of coherent explanation, I'm just going to ignore your posts.
« Last Edit: 22/01/2014 00:50:42 by Aemilius »

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Offline JP

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Re: What is free fall?
« Reply #134 on: 21/01/2014 22:41:36 »
How does one respond to an immediate and open display of hostility in a "friendly" way? Between just which two blows of his broadsword did you expect me to reach out to this Bored chemist fellow?

You're supposed to keep the tone of the conversation friendly and civil.  If you (or other users) can't do this, the thread will be locked.  Your recent responses are in line with this rule of civility.

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Offline MrVat7

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Re: What is free fall?
« Reply #135 on: 22/01/2014 08:15:27 »
Falling under action of only one force - gravity

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Offline Bored chemist

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Re: What is free fall?
« Reply #136 on: 22/01/2014 19:20:25 »
Hey Bored chemist....

Look man, in spite of the Moderators admonition, I have to stand by my characterization of your reply 113....

I can't speak for anyone else, but I didn't bother to get involved in this discussion because I got bored of refuting absurd claims about the tower falling years ago.

All the evidence supports Alan's point of view.

It fell down because some shits flew a plane full of jet fuel into it.
That fire heated the steelwork until it failed. The upper floors fell down and, since skyscrapers are not designed to take massive vertical shock loads, the rest collapsed.
It's not possible to analyse the video footage accurately enough to measure the acceleration to a high enough precision to rule out near free fall.
Typical video pictures are about 500 hundred lines high, and the image falls through about half the frame height so, at best you can measure the height of the building in each frame to about 1 part in 250.
That's simply not enough precision to rule out the suggestion that the building fell down.

You have, essentially, no evidence; but you have wasted 5 pages talking about it.

Anyone joining in with the discussion to point this out to you wouldn't have stopped you rambling on about it.

I openly challenged you to back it up (using quotes/links/articles) or take it back and you've done neither. Instead, you now seem more interested in trying to take the helm and steer the focus of the thread to grilling me about why some aspect of your invisible plane full of jet fuel claim/assertion won't work, and now you're even trying to imply an appeal to authority on my part for citing NIST data, ostensibly in support of some imaginary claim you think I've made....  I've advanced no theory, nor have I made any claims or assertions of any kind.
 
Why are you demanding answers to questions from the anonymous eighth grade dropout questioner instead of just asking Dr. Calverd, a recognized bona fide veteran research Physicist eminently qualified to answer them? As anyone can see, you're just not making any sense!

I don't have any academic credibility and I didn't come here to give answers, I came here to get answers from the brighter lights here. I didn't set out to see you in a negative light either, but until you address/account for what you wrote in reply 113, I have no choice....

At this point you've proven nothing, you've backed up nothing, you've taken back nothing, you've refuted nothing, your invisble fuel laden plane theory (if that's what it is) makes no sense and your focus on me instead of the topic is just odd.... I honestly can't see where you've really said anything at all!

In view of all that and pending some sort of coherent explanation, I'm just going to ignore your posts.

Care to show what's wrong with my assertion about the number of video lines, and the best available precision on the fall rate?
Please disregard all previous signatures.

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Offline Aemilius

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Well Bored chemist, your last post makes just as much sense as your first.... none. At least you're consistent!

It's been about three weeks now since you crash landed in this thread with the monument to irrelevance that is reply 113. All you've done since then is to repeat the same question like an old broken record player. Do you think it makes you appear intelligent endlessly waving around the same question about the precise measurement of free fall Bored chemist? Do you think that maybe it distracts people from noticing that your posts lack even a nanogram of substance/relevance? How long will you continue with this buffoonery? Everyone can see there's no logical explanation for it.... What's the deal man?

As it turns out, you're the one who's actually doing all the things you've accused me of. It is you who has made an absurd and easily refuted claim. It is you who has no evidence, essential or otherwise, supporting your view. It is you who continues to "waste space". It is you who continues to ramble on, repeating the same question in response to my repeated requests that you back up what you wrote.

Care to show what's wrong with my assertion about the number of video lines, and the best available precision on the fall rate?

I already told you, I'm just an eighth grade dropout, so I can't honestly say I know what's wrong with your so called "assertion" about the number of video lines or what the best available precision is on the fall rate. I tried to ask Dr. Calverd for his opinion of it in reply 135. My guess is the reason he hasn't responded is that he sees your post as radioactive and doesn't want to get anywhere near it. Why don't you try asking him yourself? Why are you avoiding that option here?

You may think you're being clever with all this nonsense, but the only one you're fooling is yourself. Go ahead and keep responding though if you enjoy watching what's left of your now shredded credibility in this thread repeatedly being raked over the coals (in a friendly and civil way of course) by an eighth grade dropout!
« Last Edit: 27/01/2014 06:17:16 by Aemilius »

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Offline alancalverd

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Care to show what's wrong with my assertion about the number of video lines, and the best available precision on the fall rate?

Behave, children!

If the reference point just crosses 200 lines, and there's no uncertainty in the timebase, you can estimate the fall distance to better than +/- 0.5% and the elapsed time to within a couple of microseconds by simple frame analysis. Modern videocamera timebases are very stable and consistent. The NIST graph seems pretty good to me.
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Offline Aemilius

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Excellent Dr. Calverd, and just what I intuitively suspected (but might have had a bit of trouble elucidating).

Just to be clear though.... You're saying the assertion being made by Bored chemist that it's not possible to analyse the video accurately enough to prove free fall/near free fall is in error.

Is that correct?
« Last Edit: 04/05/2016 17:42:38 by Aemilius »

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Offline alancalverd

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I think NIST can analyse a video reasonably well.
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Offline Aemilius

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I'll take that as a "Yes".
« Last Edit: 28/01/2014 08:23:30 by Aemilius »

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Offline Aemilius

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I think I'll skip any further discussion of this, it's actually starting to give me the creeps....

I have Dr. Alan Calverd Ph.D. (a well seasoned career research physicist) arguing that not only is it possible but probable that the lower 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 left), and also, incredibly, that driven on solely by gravity it quite naturally continued to accelerate so nearly to gravitational acceleration (below right) as to require very careful calculation for any difference between the two fall times to be detected.... preposterous!


There appears to be a considerable number of views of the thread but, eerily, not one member is commenting on the veracity of what I've had to say, and neither is anyone commenting on the veracity of what Dr. Calverd has had to say either.... very strange indeed!
 
A clearly irrational and insulting post made by Bored chemist slips past the moderators, but I am openly admonished for not "keeping it friendly" when I bluntly challenge/recognize his absurd baseless assertion for what it is.... a now confirmed load of rubbish!

Finally, CliffordK has explained to me (privately) that he and the other moderators decided that arguments about whether or not two jet airplanes caused the building to collapse seemed best suited to the "That CAN'T be true" subforum, though no airplane struck the building (even the NIST says airplanes had nothing to do with it) and airplanes are mentioned nowhere in the thread as having had anything to do with it either.... extremely curious!

To top it all off, compared to the meticulously factual and clearly defined hard science question I posed concerning the obvious impossibility of even near free fall occurring during any natural progressive structural failure, there seems to be no problem with topics like how much to tax the price of a drink or baggy shirts causing some guy to sweat being considered as "General Science"..... incredible!

Not meant to offend, I just don't get any of that. Thread abandoned (for now).... Lock it, leave it, do as you wish.

« Last Edit: 19/07/2015 11:17:42 by Aemilius »

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Offline Aemilius

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Re: What is free fall?
« Reply #143 on: 12/09/2014 07:43:17 »
Quote from: alancalverd
Let's have an explosion.

Right Dr. Calverd, we might as well, since, as we've both really
known all along, it's the only logical way to explain observations.

WTC7 - ANALYSIS AND CONCLUSION

A complete Prima Facie Empirically Verifiable Scientific
Method Driven Graphical Target System Analysis and
Conclusion arrived at by Process of Elimination




"Analogical models are a method of representing
a phenomenon of the world, often called the 'target system',
by another, more understandable or analysable system. They
are also called dynamical analogies." - Wikipedia


The exceptionless condition required for gravitational acceleration
to occur has been known for centuries....



....and is, as you pointed out initially "The condition under which
a body is, literally, free to fall under the influence of the local
gravitational field with no resistance to its acceleration.
"....



The Control, or source system, that appears to the right of the
Scenario, or target system, in many of the animations is
intended as a reminder of that, and also signals the
beginning of a comparison....



We can still know with certainty what condition exists beneath
an object as it falls....



....even though we may not be able to see into the space
beneath it as it does....



Buckled columns, whether one or a hundred, whether one at a
time or all at once (or any combination thereof) won't just go
from 100% to 0% when they buckle, they'll gradually
decrease in strength while they buckle
and that takes time....



The mechanism of buckling (a mode of natural progressive
structural failure), whether caused by heat....



....or by overloading....



....or by other modes of natural progressive structural failure
such as impact induced fracturing....



....or fracturing caused by overloading....



....or any other mode or combination of modes of natural
progressive structural failure absolutely cannot match or
create the exceptionless condition required for gravitational
acceleration to occur, it's literally impossible (naturally excluding
the consideration of bridges and other structures that pass through
air wherein the condition required for gravitational acceleration to
occur exists inherently as a structural feature). There is no such
thing as structural gravitational acceleration....



The progressive collapse of the building (NIST probable
collapse sequence starting with column 79 on the left)....



....that essentially happens all at once....



....is clearly physically inconsistent with what we
empirically know of natural progressive structural failure
(defined as a time consuming process of individual, sequential
or simultaneous failure involving one or a number of related
structural components). It's a physical impossibility for the
lower part of the asymmetrically damaged building
(reportedly three core columns and nine perimeter
columns) to have naturally progressively collapsed
in any way that could result in the upper part of
the building symmetrically descending as a single
unit straight down through itself.... 



....at anything near gravitational acceleration (NIST
probable collapse sequence starting with column 79 circled
below) for any period of time....



A building collapse like that seen below resulting from any
natural progressive structural failure of a steel frame building
including a 105 foot 2.25 second period of gravitational
acceleration of the upper part of the building as a single
unit is an absolute physical impossibility....



....as nowhere in the course of any such collapse or
structural failure is the exceptionless condition required
for gravitational acceleration to occur seen to arise beneath
the upper part of the building as the scenario
plays out to completion....



There is absolutely no mode or combination of modes
of natural progressive structural failure driven solely
by gravity that can ever match or give rise to the
exceptionless condition required for free fall to have
occurred at any point during it's descent....



The scenario playing out below is an absolute physical
impossibility. Just as there is no such thing as structural
gravitational acceleration
, nor is there any structural failure
mode known as natural progressive structural
gravitational acceleration
....



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

"Hold it.... right there! That's the point past which all
the welded and bolted together 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 observed beginning
and then continuing to behave in a manner indistinguishable
from  air
(below left) for at least the next eight stories,
or 105 feet
of its descent (below right). It would take very
careful calculation
to tell apart the fall times shown below
during this free fall period of the ongoing natural
progressive structural failure
"....




For the 105 foot 2.25 second period of time that we know
the upper part of the building literally fell as a single unit at
gravitational acceleration we know it can not have been
using any of it's potential energy to crush the building
contents, columns and other structural components
beneath it and undergo gravitational acceleration
at the same time (as illustrated by this
frangible impedance scenario)....



It's physically impossible for the lower asymmetrically
damaged part of the building to have naturally progressively
collapsed in any way that could result in the upper part of
the building actually accelerating as it descended symmetrically straight
down through itself as a single unit through the path of maximum
resistance (below right), and then, driven on solely
by gravity, actually continue to accelerate so nearly to
gravitational acceleration (below left) as to require very
careful calculation
for any difference between
the two to be detected....



Some other force powerful enough to quickly remove all
support
from beneath the upper part of the building as it
descended must be introduced to explain the observed
rate of descent during the 2.25 second period of gravitational
acceleration. For the 2.25 seconds that the building literally fell
at gravitational acceleration, no other force powerful enough to
quickly remove all support from beneath the upper part of the
building was seen to be introduced from outside the building,
and no other force powerful enough to quickly remove all
support
from beneath the upper part of the building is known
to have existed inside the building as an element or normal
function of it's infrastructure. For a load supported by a column
to descend at gravitational acceleration, all support must be
quickly removed, there's absolutely no other way. It must be
knocked out, pulled out, blown out, vaporized etc.
Since no eight story tall boulders were seen rumbling
through Manhatten that day that could have
quickly knocked out all support....



....and no suspicious looking Frenchmen were spotted rigging
for verinage (another form of controlled demolition) the night
before that could have quickly pulled out all support....



....and no bombs or rockets were seen to be dropped on/fired
at it that could have quickly blown out all support....



....and no giant laser beams or other secret weapons were
being tested in the area that could have quickly
vaporized all support....



....and no other force capable of quickly removing all
support from beneath the upper part of the building existed
in the building as a normal function of it's infrastructure (blue)....



....it naturally follows that whatever the other force was
that must be introduced to explain the observed 105 foot 2.25
second period of gravitional acceleration of the upper part of the
building as a single unit, it must have been introduced some time
before the event, and unless it can be shown how the other
force
that must be introduced either during or just before
the collapse of the building was introduced from outside
the building, or that it was already existing inside the
building as a normal function of it's infrastructure, the
process of elimination really leaves only one possible
explanation for the building's behaviour. Some energetic
material powerful enough to quickly remove all support
from beneath the upper part of the building during the 105
foot 2.25 second period of gravitational acceleration must
have been physically transported inside the building some
time before the event, it had to be brought in. The
explosion model is the only one....



....that can realistically match and empirically be
expected to create the exceptionless condition that
we know must have existed....



....beneath the literally falling visible upper part of
the building as a single unit during its observed largely
symmetrical descent at gravitational acceleration for
approximately 105 feet in 2.25 seconds....



The undisputed (both the NIST and independent researchers
alike agree) observation of a significant well defined period of
gravitational acceleration of the upper part of the
building as a single unit....



Stage 1 (0 to 1.75 seconds): acceleration less than
that of gravity (i.e., slower than free fall).

Stage 2 (1.75 to 4.0 seconds): gravitational
acceleration (free fall).
During Stage 2, the north face descended essentially
(displaying all the absolutely necessary, extremely important
features)
in free fall (any motion of a body where gravity
is the only force acting upon it)
, indicating negligible (so
small or unimportant as to be not worth considering)
support
from the structure (approximately 40,000 tons of
structural steel)
below.

 
Stage 3 (4.0 to 5.4 seconds): decreased acceleration, again
less than that of gravity.



....means that an explosion, or a number of explosions, must
have occurred that was powerful enough to quickly remove all
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 as a
single unit for the observed period and under the
exceptionless condition required (below left) for
gravitational acceleration to occur....



The building was brought down by explosives.
« Last Edit: 14/05/2016 16:18:30 by Aemilius »

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Offline PmbPhy

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Quote from: Aemilius
Well Bored chemist, your last post makes just as much sense as your first.... none. At least you're consistent!
A very accurate observation.

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Offline jccc

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Re: What is Free Fall?
« Reply #145 on: 21/03/2015 08:24:16 »
free fall is rolling with the punches instantaneously

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Offline Aemilius

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Re: What is Free Fall?
« Reply #146 on: 30/04/2015 19:21:43 »
Chris tells me (privately) that I've had several complaints now so genuine apologies to all for ruffling any feathers (including yours Chris), that was never my intention. From the start all I've really been interested in, all I've really been trying to do, is get to the bottom of it.... and I have now.

Thanks again for engaging me and for helping me sort it out Dr. Calverd, it was a real marathon, and I had fun making the animations too, wouldn't have come up with them otherwise.

I must say though (inhaling deeply) that in view of the overwhelming simplicity of the governing physical principle here involving the Law of Conservation of Energy as applied to a falling body I remain completely baffled as to why there was never any other input by any of the other people here apparently so well qualified to judge the analysis that really should have quickly and naturally led to a simple confirmation or denial by consensus of the veracity of the information conveyed by it as one would normally expect in response to such a fundamentally structured high school level empirically verifiable analysis like this (Reply 143) from such a venerable academic institution as University of Cambridge.... where Isaac Newton himself once held the vaunted Lucasian Chair.

Emile Cole
« Last Edit: 17/12/2015 20:17:13 by Aemilius »