Gage's next debate

[Sunstealer]

SLIDE: The melting of steel girders... or the debate is over.
With The melting of steel girders: Some Sulfidized steel melted at temperatures1000 degrees lower than pure steel, but not enough to explain the global collapse.

Yes be careful with this one. The Fe-O-S eutectic that was liquid is a very, very small quantity - it's not bulk melting, but grain boundary melting; so around 20µm (microns) wide. Also note the temperatures because sometimes there's a mixup between °F and °C and even °K. For the record - pure Iron Fe melts at 1538°C and the eutectic Fe-O-S is 940°C.

SLIDE: Several tons of molten steel or iron in the debris pile of all three buildings . or the debate is over.
As for allegations of molten steel or iron: There were several tons of melted aluminum discolored by debris with a melting point of only 1200 degrees.

liquid metal doesn't mean liquid steel. Lots of metals, alloys, glasses etc melt below 1538°C. Witness statements are pretty much invalid because you can't tell what a material is just by looking at it's colour. Molten=/=liquid.

SLIDE[The billions of previously molten iron microspheres or the debate is over. ]

And the iron microspheres? In 70s, workers welded tens of thousands of steel beams and splattered microspheres. Even if they were created on 911, the RJ Lee study said, “Considering the high temperatures reached during the destruction of the WTC... Iron - rich spheres... would be expected to be present in the Dust.”

Yes, he doesn't understand that microspheres are natural and fly ash is used in concrete. Burning fires will create them, burning wood creates microspheres. Also these spheres are not pure iron so melting temperature will be lower. Saying only thermite creates these spheres is nonsense.

Slide: The red-gray chips of advanced energetic nanothermite composite material found in the WTC dust. or the debate is over."
Finally, those thermitic chipst: 1.) In that experiment, the chips were heated in air; thermites burn without oxygen, so they failed to prove thermites. 2.) Richard flashed two controversial spectographic charts on the screen that looked different, and he never explained why they prove thermites. That’s not debate, that’s obfuscation. 3.) The experiment did not separate out the naturally occurring elements and chemicals in the World Trade Center from the alleged thermitic compounds. 4.) At least two 9/11 Truth advocates have tried to do followup studies on the dust. Frédéric Henry-Couannier wrote,"Eventually the presence of nanothermite could not be confirmed.” Mark Basile got the red-gray chips to burn in air, replicating the error of the original experiment and not even measuring the energy released. I can’t take seriously fellow Truthers cooking red chips and calling it a scientific experiment. RJ Lee did a major study of the dust for Deutsche Bank in 2003 and found iron microspheres but not thermites. I am baffled that these red-gray samples have not been submitted to a reputable lab like RJ Lee for independent testing for thermites.

Yep that last one would put him in a very tight spot although there is no need to add the "testing for thermites" caveat. Simply send the samples to an independent lab asking for the characterisation/identification of the material. No other information is required. It's very, very cheap to do these days.

I'd be interested to know what he thinks is actually producing the spheres in the DSC. When you look at the photos in Fig 20 it's plainly obvious that it's predominantly the gray layer that has formed the spheres. I've not touched on that before. The red layers haven't fully reacted. If the red layer is thermite then why is it the gray layer that is forming the spheroids? (My own hunch is a gamma-Fe2O3 to alpha-Fe2O3 phase transition - but I need more papers/research)

 

[fourtoe]

I'm listening to it now. The introduction is absurdly long. It shouldn't take 15 minutes to introduce the ground rules and the debaters.

 

[chrismohr]

Sunstealer reply

Yes be careful with this one. The Fe-O-S eutectic that was liquid is a very, very small quantity - it's not bulk melting, but grain boundary melting; so around 20µm (microns) wide.

Just to be sure: except for small amounts of eutectic steel, there were no melted steel girders at WTC? That's my understanding from my research. Also, weren't there big holes in those few girders from some of the eutectic action? Was that corrosion and not melting?

Also, good idea about just telling RJ Lee or someone "Here's dust samples, what's in it?" Until I thought of this today I never realized that labs are set up for this kind of thing, and now you tell me it would be affordable to have it done. I used to think it would be way expensive, but even so, I hear Charlie Sheen's a Truther and he's making bundles off his tour these days. Someone could ask him for the funding???

 

[fourtoe]

Can anyone direct me to a link that I can download the .mp3 of the debate so I can listen to it on my iPhone? That would be most awesome.

 

[chrismohr]

Can anyone direct me to a link that I can download the .mp3 of the debate so I can listen to it on my iPhone? That would be most awesome.

Try this: http://noliesradio.org/archives/GageVMohrDebate2011-0306_web.mp3

Chris Mohr

 

[chrismohr]

Chris Mohr's Epilogue II for Gage Debate: Building 7

OK Gang,

Here is my first draft of Epilogue II of the March 6 debate, where I explain the free-fall of Building 7. Again, because of time constraints, if anything has to be added, something else has to be taken out. If anyone wants to look it over for clarification, I'd be grateful.

In the meantime, the Chris Mohr Debater's Helper Award goes to none other than Ryan Mackey, without whom I would have had a much less successful debate. Ozeco gets second prize, and Sunstealer third. Honorable mention goes to my opponent Christopher7, who keeps me on my toes.

Thanks to all,
Chris Mohr

PS I asked Richard Gage directly about nanothermites vs thermates, which was it, what am I debating against? His answer is below.


BUILDING 7 EPILOGUE II

At the very beginning of the debate, Richard Gage said, "My opponent must resolve the symmetrical, free-fall collapse of Building 7, or the debate is over.” Let’s go over it in more detail. Slide of wide building. First, gravity pulls things straight down unless a lateral force like an earthquake pulls it to the side, especially in a wide building.

Free-fall acceleration means no net resistance, meaning resistance can be canceled out by other forces. It does not mean controlled demolition; the Southwark Towers demolition for example, took 7.4 seconds, not 4.5 freefall seconds. NIST’s freefall model “showed the extberior columns buckling and losing their capacity to support the loads from the structure above.”

Building 7's structural integrity deteriorated as it burned, and firefighters feared a collapse. Video of firefighter Miller talking about structural problems and imminent collapse of Bldg 7: fire can cause structural degradation and, yes, collapse of a steel-framed skyscraper.

Freefall... and faster-than-freefall... collapse lasted only 8 stories out of 47 and here’s how. I will speak slowly...

STICK DEMO Imagine this stick is a column. Pushing down, it kinks a tiny bit at first, then it breaks, as many columns did. The columns were all interconnected so the load was shared.

NIST DIAGRAM OF COLLAPSE ACCELERATION SLIDE.

Number 1.) The final perimeter collapse started almost imperceptibly, like the stick barely bending, then, gradually, acceleration increased towards free fall for eight stories out of 47, often slightly faster than freefall, as you can see from the dots above the freefall curve, for eight stories. In the final seconds of the collapse it slowed down.

Number 2.) New Collapse video The east penthouse collapsed. You can see sunlight shining (Time video clip so sunshine light happens here) through the upper left windows, and more windows breaking along the left side as the penthouse collapsed to the ground. This was an asymmetrical interior collapse, not a symmetrical controlled demolition. For 8 seconds the interior caved in on itself, much as described by NIST

Number 3.) SLIDE OF MY DIAGRAM. Debris fell inside the center of the building and down.

Number 4. ) The debris pile spread out at the bottom and pushed out against columns randomly, stressing the columns with irregular horizontal loads.

Number 5 at the top.) (Kink) The columns, unevenly weakened from seven hours of fires, were also pulled in from the breaking support beams above. The small kink along the top of the building was evidence of columns about to snap.

Number 6.) The perimeter columns buckled, pushing their loads to other columns at the speed of sound, triggering more column breaks at the weaker welded connections, causing gradually increasing acceleration as structural resistance in the perimeter columns quickly gave way one by one.

This begins stage two of the perimeter collapse. Acceleration slightly exceeded 100% of free fall for much of these eight stories. How?

Number 7): An 8-story chunk of floors held onto a perimeter wall. Those attached floors literally torqued the perimeter wall down those eight stories. This leveraged pull down overwhelmed any remaining structural resistance and resulted in less than net-zero resistance and a barely faster than free-fall drop.


Number 8.) As the perimeter crashed into the debris pile, its descent was slowed. This is the third phase of the collapse sequence.

Controlled demolition cannot explain greater than free-fall acceleration, and buildings being brought down by controlled demolition usually collapse at slower than free-fall. Leveraging by the 8 stories of attached interior floors does explain it. Richard, on the other hand, asserts that noisy explosive nanothermites were used to bring down the Twin Towers and quieter Thermate for Building 7. Thermate “cuts through steel like a hot knife through butter,” but much too slowly for Precise demolition! And if thermates were used on the outside columns, there would be hundreds of blinding lights through the windows with no dust to block the view.

 

[fourtoe]

Try this: http://noliesradio.org/archives/GageVMohrDebate2011-0306_web.mp3

Chris Mohr

Awesome! Thank you sir!

 

[Christopher7]

OK Gang,

Here is my first draft of Epilogue II of the March 6 debate, where I explain the free-fall of Building 7. Again, because of time constraints, if anything has to be added, something else has to be taken out. If anyone wants to look it over for clarification, I'd be grateful.

In the meantime, the Chris Mohr Debater's Helper Award goes to none other than Ryan Mackey, without whom I would have had a much less successful debate. Ozeco gets second prize, and Sunstealer third. Honorable mention goes to my opponent Christopher7, who keeps me on my toes.

Thanks for the honorable mention but I have failed to keep you on your toes. I find your explanation of FFA a bit flat footed.

No worries mate, we agree to disagree in an agreeable manner.

What is your response to "The fire that supposedly started the collapse had gone out over one half hour before the collapse" ?

 

[fourtoe]

I have an hour and a half left of the debate and so far I would say that this one is up there with Gravy's debates.

Good job Chris Mohr, you definitely nailed Gage on his hand waving the mass of the top block crashing onto the rest of the tower. Gage's analogy with the apples was awful.

Also I am so so so SO sick of Gage talking about pyroclastic flows. That is a geological term used for a specific type of phenomena.

And Pompeii was devastated by a pyroclastic flow. We didn't find ppl dead and in cased in ash in any way resembling what happened at Pompeii or other areas where pyroclastic flows have devastated a settlement.

If the materials in the clouds of dust are to be compared to a pyroclastic flow then these ppl should be dead. What happened sucked but thank the Flying Spaghetti Monster that these WERE NOT pyroclastic flows.

I noticed that there were three specific things mentioned by Gravy in his debate with Gage that Gage was able to slip out of answering because of the stupid debate format Gage and the moderator chose.

1) Concerning the concrete turning to dust:

As we examined the WTC-debris sample, we found large
chunks of concrete (irregular in shape and size, one was
approximately 5cm X 3 cm X 3cm) as well as medium-sized pieces
of wall-board (with the binding paper still attached). Thus, the
pulverization was in fact NOT to fine dust, and it is a false
premise to start with near-complete pulverization to fine powder

This is a passage from a STEVE JONES paper!
The very last paper on the page.

2) Concerning the Fe microspheres:
Gage uses an RJ Lee paper talking about Fe-rich microspheres and even said, referring to the Fe-rich microspheres, that RJ LeeInc. was talking about them "because they didn't know what the hell it was!" Well here is a quote from that paper that Gravy responded with:

Particles that either were formed as a consequence of high temperature or
were modified by exposure to high temperature are important WTC Dust
Markers for WTC Dust. Fires that were a part of the WTC Event produced
combustion-modified products that traveled with other components of WTC
Dust. Considering the high temperatures reached during the destruction of
the WTC, the following three types of combustion products would be
expected to be present in WTC Dust. These products are:
• Vesicular carbonaceous particles primarily from plastics
• Iron-rich spheres from iron-bearing building components or contents
• High temperature aluminosilicate from building materials

Reference #2 on this page

3) Gage says that 118 ppl saw flashes and heard loud noises before/during the collapse, but of all of them only 2 said they actually saw flashes. This is very sketchy of Gage because what he did was take those two accounts and quoted them throughout his .ppt without identifying who made these quotes to make it seem like more ppl saw flashes.

Gravy pointed this out in 2008! And Gage has yet to take it out of his .ppt, he still does it in slides 142 and 155 for his 30 min. presentation and on slides 201 and 206 for his hour presentation.
Gage's slides

Although I must admit I recall there being more slides containing the two quotes the last time I looked through his .ppt, and well, being slightly less deceptive is better than nothing right?

If you haven't all ready, I'd suggest watching the debate between Gravy and Gage:
Part 1
Part 2

 

[LashL]

This thread is once again going afield. It's about Gage's last debate with Mr. Mohr, not about the minutiae of the collapse of 7WTC and the NIST report relating to that. If you want to discuss the minutiae of the collapse of 7WTC and the NIST report relating to that, there are other perfectly cromulent pre-existing threads for that.

Replying to this modbox in thread will be off topic  Posted By: LashL

 

[chrismohr]

Thanks for the honorable mention but I have failed to keep you on your toes. I find your explanation of FFA a bit flat footed.

No worries mate, we agree to disagree in an agreeable manner.

What is your response to "The fire that supposedly started the collapse had gone out over one half hour before the collapse" ?

I've watched the back and forth over this argument and see you and others (both sides with more technical background than me) denying and asserting there were fires on floor 12 right to the end, that damage from fire can't be undone, my own suggestion (borrowed from Ryan Mackey) that thermal expansion/sagging on floor 12 could have been followed by thermal contraction from the cooling while keeping the sagged shape thus causing still more damage and stress, etc etc etc. I doubt we'll ever know exactly what happened inside the building as it collapsed. If you're asking me to accept that floor 12 cooled down making NIST wrong therefore controlled demolition, no, I'm not biting.

 

[chrismohr]

Two questions including David Chandler on Free Fall of Building 7

Two more things for this post-debate.

First, so far I have gotten good feedback from the JREF crowd on my performance in this debate. Am I right in asserting that I represented the science of natural collapse vs controlled demolition well (considering I'm not a scientist)? I'm asking this question especially to the engineers, physicists etc on JREF who agree with Natural Collapse. I know there have been some things I could have said better, but do we have consensus that generally I did pretty good to very well? Yes or no, I do want to know.

Second, in preparing the Epilogue to this debate, I wrote to David Chandler and ran the free-fall of Building 7 hypothesis by him (as I have run other things by Richard Gage, Kevin Ryan, etc). He had a technical retort I considered very good, and told him so. I want to run it by you all and get your take on it:

Chris: Specifically with Building 7,
>> whatever residual resistance from the broken perimeter columns could have
>> been canceled out by the inward torquing of the building from large chunks
>> of floors still attached to the perimeter walls, a leveraging force that
>> would speed up the collapse during those 2.25 seconds.
>
> David: Man-on-the-street intuition doesn't constitute valid physics. This
> scenario has no merit. Think of the falling chunk of building as a
> "system". Put a dotted line around it as the boundary of the system.
> How the center of mass of the system moves depends on the interactions
> across the system boundary. Those interactions are the resistance
> from the lower section of the building and gravity. Anything going on
> within the system (such as any torquing, etc., that you imagine) have
> no effect on the motion of the system as a whole. In order to get
> freefall you need the resistance to be totally removed so gravity is
> the only force acting. The freefalling block can do no work on its
> surroundings, or it would be slowed, so the support was removed by
> something other than the falling block. (Explosives, for instance.)
> By the way, while it is in freefall there should be no stresses within
> the system either. The falling system would be in a "relaxed" state.
> Think of everything floating around in the space shuttle. That's an
> example of literall freefall. There is no way around it. Freefall
> really does imply that all support was knocked out by something other
> than the falling block.

Thanks for any feedback on both items, Chris

 

[Fly Poster]

Those interactions are the resistance
> from the lower section of the building and gravity. Anything going on
> within the system (such as any torquing, etc., that you imagine) have
> no effect on the motion of the system as a whole. In order to get
> freefall you need the resistance to be totally removed so gravity is
> the only force acting. The freefalling block can do no work on its
> surroundings, or it would be slowed, so the support was removed by
> something other than the falling block.

Did Chandler not find that faster than gravity occurred? Pointing away from explosives in favour of moment of force.

 

[Oystein]

...
Second, in preparing the Epilogue to this debate, I wrote to David Chandler and ran the free-fall of Building 7 hypothesis by him (as I have run other things by Richard Gage, Kevin Ryan, etc). He had a technical retort I considered very good, and told him so. I want to run it by you all and get your take on it:
...
> David: ... Think of the falling chunk of building as a
> "system". Put a dotted line around it as the boundary of the system.
> How the center of mass of the system moves depends on the interactions
> across the system boundary. Those interactions are the resistance
> from the lower section of the building and gravity. Anything going on
> within the system (such as any torquing, etc., that you imagine) have
> no effect on the motion of the system as a whole...
...
.Thanks for any feedback on both items, Chris

Two answers to this second question:

1.
Those of us who hypothesize that the falling building core pulled the perimeter down via the floor trusses are treating the facade only as the "system" whose center of mass fell at g, or even slightly faster for moments. The torque experienced by that system would thus be external to the system in question.
David, on the other hands, seems to imply that the floor trusses, and possibly the core, are part of that "system" that fell at around g. This is a speculation on his part, as we can't observe anything behind the facade. Maybe he is right, maybe he is wrong.

2.
If your "system" is already rotating while falling, then you would observe a higher vertical acceleration on one side, and a lower on the opposite side, without additional external forces.
(This is only theoretically true, and I think doesn't apply to the north face)

 

[newton3376]

Chris: Specifically with Building 7,
>> whatever residual resistance from the broken perimeter columns could have
>> been canceled out by the inward torquing of the building from large chunks
>> of floors still attached to the perimeter walls, a leveraging force that
>> would speed up the collapse during those 2.25 seconds.
>
> David: Man-on-the-street intuition doesn't constitute valid physics. This
> scenario has no merit. Think of the falling chunk of building as a
> "system". Put a dotted line around it as the boundary of the system.
> How the center of mass of the system moves depends on the interactions
> across the system boundary. Those interactions are the resistance
> from the lower section of the building and gravity. Anything going on
> within the system (such as any torquing, etc., that you imagine) have
> no effect on the motion of the system as a whole. In order to get
> freefall you need the resistance to be totally removed so gravity is
> the only force acting. The freefalling block can do no work on its
> surroundings, or it would be slowed, so the support was removed by
> something other than the falling block. (Explosives, for instance.)
> By the way, while it is in freefall there should be no stresses within
> the system either. The falling system would be in a "relaxed" state.
> Think of everything floating around in the space shuttle. That's an
> example of literall freefall. There is no way around it. Freefall
> really does imply that all support was knocked out by something other
> than the falling block.

Thanks for any feedback on both items, Chris

I don't quite understand what Chandler is doing here....

Is he trying to say the "system" or falling section is completely disassociated from the rest of the structure?

By using the example of the space shuttle "floating" it appears he is assuming that free fall means the section has no real interactions with any other part of the remaining structure....

 

[ozeco41]

... Chris: Specifically with Building 7,
>> whatever residual resistance from the broken perimeter columns could have
>> been canceled out by the inward torquing of the building from large chunks
>> of floors still attached to the perimeter walls, a leveraging force that
>> would speed up the collapse during those 2.25 seconds.
>
> David: Man-on-the-street intuition doesn't constitute valid physics. This
> scenario has no merit. Think of the falling chunk of building as a
> "system". Put a dotted line around it as the boundary of the system.
> How the center of mass of the system moves depends on the interactions
> across the system boundary. Those interactions are the resistance
> from the lower section of the building and gravity. Anything going on
> within the system (such as any torquing, etc., that you imagine) have
> no effect on the motion of the system as a whole. In order to get
> freefall you need the resistance to be totally removed so gravity is
> the only force acting. The freefalling block can do no work on its
> surroundings, or it would be slowed, so the support was removed by
> something other than the falling block. (Explosives, for instance.)
> By the way, while it is in freefall there should be no stresses within
> the system either. The falling system would be in a "relaxed" state.
> Think of everything floating around in the space shuttle. That's an
> example of literall freefall. There is no way around it. Freefall
> really does imply that all support was knocked out by something other
> than the falling block.

Thanks for any feedback on both items, Chris

He is cheating on where he places the system boundary. (EDIT: PS And on the "within system" dynamics) But I would need to think carefully even then I doubt we can get it "man in the street" understandable...

...which is the massive advantage that Gage Chandler et all manipulate to their own ends.

...but we knew that didn't we.

There is an Aussie saying "Life wasn't meant to be easy" - allegedly said by a senior political who got caught sans trousers on one occasion.

I'll try to put brain in gear tomorrow AU time and see what I can write.

Eric C

 

[chrismohr]

I do want to repeat the first part of my question and ask as a favor that this be addressed by those of you who have heard the debate (especially physicists, engineers, etc). I'm not just asking for strokes, I have a good reason for wanting to know, preferably in the next day or so (and it won't require as much hard thought as the techncial question): So far I have gotten good feedback from the JREF crowd on my performance in this debate. Am I right in asserting that I represented the science of natural collapse vs controlled demolition well (considering I'm not a scientist)? I'm asking this question especially to the engineers, physicists etc on JREF who agree with Natural Collapse. I know there have been some things I could have said better, but do we have consensus that generally I did pretty good to very well? Yes or no, I do want honest answers from the natural collapse advocates.

 

[R.Mackey]

So far I have gotten good feedback from the JREF crowd on my performance in this debate. Am I right in asserting that I represented the science of natural collapse vs controlled demolition well (considering I'm not a scientist)? I'm asking this question especially to the engineers, physicists etc on JREF who agree with Natural Collapse. I know there have been some things I could have said better, but do we have consensus that generally I did pretty good to very well?

See, here's the thing. Science and engineering don't take place in debates. Repeatability, precision, and detail are important. Sounding good and swaying the opinions of an audience, particularly one who may or may not have any relevant training or experience, are not.

In my opinion you did pretty well, considering. By that I mean you are relatively new to the topic, you took on someone who literally hawks his screed in front of audiences for a living, you did so in front of an overwhelmingly hostile audience. You did make a few mistakes and missed a few opportunities, but on balance, you did well.

However, in real science and engineering, those few mistakes (a) would be enough to get people killed, and (b) would be easily caught and corrected by even a superficial review.

Your best asset in debate, sadly, is not your knowledge or preparation or anything -- it's the fact that you are not an engineering professional, and you are not someone with a long history in debunking. If any Truthers were swayed by your appearance, it would be because of this, not because of what you said or how you said it. Then again, we're talking about folks who resist the logical equivalent of two-by-fours to the head with astounding regularity.

When one enters science, one tacitly accepts that one's work is rarely understood by the public or treated accurately in the media. The majority of people don't even understand simple calculus, for crying out loud. For them to misunderstand complex building performance and the course of scientific investigation is, frankly, unsurprising and uninteresting -- and that's the general public I'm talking about. How the razor-thin wedge of paranoiacs within the general public react should be even less surprising.

 

[fourtoe]

I don't quite understand what Chandler is doing here....

Is he trying to say the "system" or falling section is completely disassociated from the rest of the structure?

I know you want physicists and engineers and stuff to answer your questions but when I read Chandler's response to your email I thought the same thing as Newton...I think. It does sound like Chandler is trying to weasel out of factoring in the stuff you talked about by disassociating the system from the rest of the structure.

See, here's the thing. Science and engineering don't take place in debates. Repeatability, precision, and detail are important. Sounding good and swaying the opinions of an audience, particularly one who may or may not have any relevant training or experience, are not.

I think good way to go about this debate is pointing out any specific misrepresentations Gage makes in his arguments. People will fall apart if they hear things like, "angular momentum" or "eutectic" but most people will be able to understand you when you say something like, "Gage when ppl say they heard a count down of some kind, you do realize that Kevin McPadden said that it was a Red Cross guy that heard the countdown. Are you suggesting that red cross was in on the CD?"

Also, regarding the bomb-sniffing dogs, there were bomb sniffing dogs at the WTC that day, one of them died--Daria Coard. There were also like over 200 bomb-sniffing dogs at Fresh Kills Landfill--dogs that were trained to sniff out incendiaries and they found nothing.

Your best asset in debate, sadly, is not your knowledge or preparation or anything -- it's the fact that you are not an engineering professional, and you are not someone with a long history in debunking. If any Truthers were swayed by your appearance, it would be because of this, not because of what you said or how you said it. Then again, we're talking about folks who resist the logical equivalent of two-by-fours to the head with astounding regularity.

This is pretty much why Gage debated you. It seems like Gage is only willing to debate ppl who don't have expertise in this field. The closest he got to was Dave Thomas, who was a physicist but was new to the tediousness that is 911 CTs. Other than that he debated Gravy: a tour guide and Ron Craig: a film teacher.

Also when Gage talks about the 1,400 engineers and architects who support the CD CT, you can talk about the 100s of 1000s of engineers and architects who don't support a CD CT, not to mention the 200 engineers who worked on the NIST report.

The seismic evidence you presented I think would also be a good angle to go at this because it is all science-y but a little easier to understand.

Also, THANK YOU for correcting Gage about the pyroclastic flows thing, that made my day when I heard it.

 

[ozeco41]

@ChrisMohr
Recalling my promise to "I'll try to put brain in gear tomorrow AU time and see what I can write."

My first answer was correct but whether I can put it in "man in the street" language is a different matter. I said:

He is cheating on where he places the system boundary. (EDIT: PS And on the "within system" dynamics)....

On reflection both those criticisms amount to the same single issue which is that he "begs the question". His assumptions rely on a free falling entity which he describes as a "system". He then places the system boundary to "prove" his prejudgement and to exclude the type of mechanism we postulate. Then he circles round the logic to in effect confirm his initial assumption. We have seen another example of that trick (or error) here labelled "Missing Jolt" but that is a side track.

This is the guts of the issue - "we", through you, have suggested that moment or torqueing can get one visible bit of structure moving at equal or exceeding free fall acceleration. That statement is true. It works because gravity applies force effectively to the centre of mass of a body. If one end of the body is restrained and the other end is further out than the centre of mass gravity acting effectively at the centre of mass will cause the part of structure to rotate. And the part of the structure further out from the restrained point than the centre of mass will exceed g acceleration. Straight out "multiplication" due to different lengths of the lever. See the video clip previously posted.
http://www.youtube.com/watch?v=BV7TPvk__kE&feature=featured

One arrangement of that set-up could look like this:

So we have a long beam attached to some pivot inside the building - shown as "pivot" on the right. The pivot is fixed. All the beam left of the pivot including the two masses is free to fall. The largish mass in the middle includes the centre of mass ["CoM"] of the whole set-up because the "Facade" on the left has relatively small mass. So the centre of mass of the lot is slightly further out than the CoM of the large mass alone. (More explanation if needed)

Gravity drags down the overall CoM which accelerates at "g" - the lever throws the facade faster than "g".

Now that is how we envisage it. Chandlers version has the pivot falling together with the two masses as part of his isolated system. With the pivot moving with the masses there is no restraint for the pivoting lever action to throw the facade.

So going to Chandlers explanation with my comments interspersed in blue:

[Lots edited out]...
David: .....Put a dotted line around it as the boundary of the system. (Eric's comment - Valid concept BUT he puts the boundary in the wrong location) How the center of mass of the system moves depends on the interactions across the system boundary. (Eric's comment - TRUE) Those interactions are the resistance from the lower section of the building and gravity. Anything going on within the system (such as any torquing, etc., that you imagine) have no effect on the motion of the system as a whole. (Eric's comment - TRUE - but he is assuming the wrong boundary on the system.) In order to get freefall you need the resistance to be totally removed so gravity is the only force acting. (Eric's comment - Here he "Begs the Question".) The freefalling block can do no work on its surroundings, or it would be slowed, so the support was removed by something other than the falling block. (Eric's comment - He is totally ignoring the possibility we postulate.) (Explosives, for instance.) (Eric's comment - And makes his prejudgement explicit) By the way, while it is in freefall there should be no stresses within the system either. (Eric's comment - Let him get away with that - for his wrong assumption. It isn't necessarily true even then.) The falling system would be in a "relaxed" state. (Eric's comment - that is one likely option but not exclusive.) Think of everything floating around in the space shuttle. That's an example of literall freefall. There is no way around it. Freefall really does imply that all support was knocked out by something other than the falling block. (Eric's comment - He is still locked within his false paradigm)

Thanks for any feedback on both items, Chris

Now from this point we can take a two step process - viz:
Step One "Do you understand or is more explanation needed?"; THEN
Step Two It seems far too complex for the debate format - can we pick out the essential points OR do we write a short dismissal of their counter claim with simplified logic.

Over to you.

Eric C


PS this is fun

PPS Should anyone see an error could you please let me down gently.