The science of why it had to be controlled demolition, in laymen's terms

Originally posted by Larry B.The toppling swing back you speak of could just be spring-back inherent to steel.

NIST's report shows dissassociation of many columns, the ones that remain would have to be extremely strong to spring the entire top section back, while at the same time undergoing a global collapse. Logic dictates they would not have given way in the first place, if they had the strength to spring it back.

Originally posted by Larry B.There are many things not ever mentioned like the fact that the Aircrafts fuel and fluids combined with the onboard oxygen for emergencies would have created a very hot fire. Also many of the plastic/synthetic items in the building may have altered the fire properties.

The fuel and oxygen would have to be concentrated in very specific area's to have an effect like this, amidst all the chaos of the impacts, I find this highly unlikely. What was the continuous supply of fuel to combust with the oxygen? The oxygen in these systems would also expand, which would lower the temperature and be at odds with being concentrated in the right spots.

reply to post by ZeuZZ


Thanks for the reply, ZeuZZ. First, let me comment about the "laymens terms". When I originally pulled up your thread, the title read lamens instead. I had pretty well assumed what you intended, but checked it to be sure. Then after your response to another poster and your touting a PhD, my initial knee jerk response was "Oh boy, another alleged physicist". Sorry, but you see so many claiming such and such background to reinforce their argument, but it is usually based on little fact and mostly opinion. Essentially, you end with nothing more than a pissing contest with them. So, when I originally started my reply, I was going to point out my disbelief in your credentials by some of the bigger flaws in your original post then decided to take another route. I had intended to change that point to simply asking if you really meant laymen instead of lamen. A silly point to nitpick a trivial thing as a typing error. I can only admit I'm human and prone to a knee jerk response like the rest of the world.

Now to get back to the matter at hand, the tipping of the upper floors and the lack of resistance.

You point that up to the point of collapse that there were 100 floors holding up the remaining upper floors, the tip should have continued, but because the lower floor was no longer providing support that it is proof of demolitions.

Again, I will tell you that it does not prove explosives were used, it simply proves that the support was no longer there and could have been caused by something other than explosives. Also, at the point that the upper section was still in contact with the lower, less damaged (it is foolish to assume that damage was contained where we could see the hole in the wall, otherwise we are ignoring stress damage caused by inertia) area, the whole floor did not need to collapse, only where the physical point of contact failed. Once the collapse began, just the estimated live load weight of the upper floors was more than enough to overwhelm the lower floors. The whole structure did not fall at once or from the bottom up; but fell on the floor below, then that mass landed on the next floor and so on. That action right there negates controlled demolition (CD), since CD relies on working from the bottom up.

Then, you are also talking about the core columns and how they are undamaged. I believe your assumption is incorrect, because you are ignoring the less obvious damage caused at the time of impact. If the buildings had been struck on the uppermost floors (ie 105 and above) the stress damage would have only affected a small percentage of the floors below, allowing the stress to be spread down the rest of the structure.. Instead, the point of impact was, let's say, about 2/3 of the way up. So we have the stress caused on a percentage above and a percentage below the impact. Because the lower 2/3 of the building were forced to bow out then return to a starting position, the core had to absorb it as well. What would have started as minor damage (stress fractures, popped rivets and sheared bolts) to the core would have worsened as the continual stress of any building movement, further light failure of supporting members (fire and heat), and the redistribution of the weight took it's toll.

My reason for posting is not to defend or refute any theories regarding who was behind 9/11, how they executed the destruction of the WTC towers, or why.

I'm posting to clear up, and correct, some misconceptions and false statements regarding the physics of falling objects and angular or rotational momentum.

In the following, admitedly crude sketch, the gapping wedge on the right side of the left image represents the damage caused by (insert your favorite theory here). The central axis of the bldg is a dashed line and the black dot represents the approx. center of mass of the upper portion of the building. The Black arrow Fg represents the force vector of Gravity (the only significant force vector acting on the upper portion before catastrophic failure). The Fam arrow represents the angular momentum force vector.

Important note: The size of the damage zone is greatly exaggertaed to make visualization easier.

The next frame (image to the right) represents what happens immediatley after the last structural components supporting the upper section fails.

At this time, the upper portion tilts (as everyone has seen). It is now undergoing two main acceleration vectors....The Fg vector (gravity) and the Fam vector (angular momentum). As you can see, the center of mass is still well within the footprint of the building.

I have not calculated Fam or Fg because I don't have the mass of the upper section handy, but it is very safe to assume Fg will be much stronger than Fam because the lateral acceleration of the upper portion is certainly much lower than accleration due to gravity based very simply on the vector components.

With the center of mass still within the footprint of the bldg and the vertical force vector overwhelming the angular force vector, most of the mass of the upper section falls down onto the lower section causing a cascading structural failure of the lower section.

Originally posted by ZeuZZ

Please could you be more precise and give some direct quotes from these sites in relevance to laws of physics. That would be much appreciaited. Thankyou.

Actually, I, nor anyone else, has to. I'll just wait for you to refute each of the papers.

Cheers.

Originally posted by darkbluesky

I have not calculated Fam or Fg because I don't have the mass of the upper section handy, but it is very safe to assume Fg will be much stronger than Fam because the lateral acceleration of the upper portion is certainly much lower than accleration due to gravity based very simply on the vector components.

It is very safe to assume?? So we agree we don't know the mass of the toppling part of the building, but I think we can agree it is quite massive... Now look at your drawing... The vector you designate as Fam has less force than the vector you designate as Fg, again I agree.... Now look at what your Fam vector is pointing at... exactly.. thin air... Which I think it is safe to assume offers a LOT less resistance than what your Fg vector is pointing at... A massive, and (should be) structurally sound building...

This is my first post and I only posted because the ignorance of this comment really got my goat. I do not profess to know what happened on 9-11, but IMHO the Laws of Physics are not something anyone can "argue" with... To do so only demonstrates your ignorance... To use these same laws in a seriously flawed logical argument as the one above is something I cannot even begin to comprehend.... Oh well to each his own I guess...


[edit on 12-12-2007 by JayDub113]

I have listened to all the available evidence of that day and I also remember stopping what I was doing in my livingroom dumbfounded and staring in disbelief as the day unfolded. I like everyone else watched hours of CNN and other news and if it wasn't for brave intelligent people like the ones who made loose change, I would have continued to believe all the media reports of that day. I cannot believe that anyone who truly takes the time to investigate the evidence on all levels can conclude any other way. If you dont believe that 911 was an inside job then thats O.K. We take nothing away from the heroic efforts of the firemen or the braveness of helpful citizens but whoever was behind the tragedies of that day should pay.
We the common people have died on their battlefields, paid their taxes, suffered their injustices but they don't own us.
I can't predict the coming events of the world but its really time to give our loyalty to the one that does own us...........Our creator.

I hope this hasn't been brought up yet, I only scanned the second page.

My only questions left about this situation are:

How could they have timed the full collapse right with the top floors giving out? Even in CD 's switches are very delayed.

Also, is it possible that large buildings like this have pre-installed bombs in the supports so that when the structure is compromised they blow to limit devastation of the rest of the city? I mean, with gov't structures I could see this being a consideration, and I don't think anyone can watch B7 fall without thinking it was controlled. Its obvious.

Other than that, I was completely unimpressed by all the data until recently, when I began reading the stuff. There are plenty more pieces of empirical evidence showing a controlled demolition than a couple of planes destroying three buildings probably millions of times larger.

Originally posted by ZeuZZ
7. Horizontal Ejections: But gravitational energy is, of course, vertical, so it cannot even begin to explain these horizontal ejections.

i agree with many of these points, but this one just seems wrong. i can't see how that is valid. Imagine a toothpick, pointing straight up. if you push down on it, it will bend a little. push harder, it will break, and splinters will fly out horizontally. wouldn't this be the same effect with a building?

Originally posted by coughymachine
Here's a pretty good video showing what looks to me like the continuing tilting/rotation of the upper section. The onset of the collapse occurs around 1:58. Watch as the fabric of the building itself disappears into the debris cloud. The cloud swells at the point where the building would be predicted to be, almost embossed.

That is a very good angle to see the initial toppling, thanks for posting that one. Its just a shame that you can only see the side corner of the building through huge amount of dust. Thats another thing, there is no way that the dust would have been that fine and dispersed without there being a very large amount of energy there.

Think about it, if you drop a concrete brick, say from 200 metres, it will certainly smash on impact and you get some big parts, lots of pebble sized pieces, and a small fraction of dust; but you definately do not get a dense cloud of smoky texture dust created.

Early in the collapse, say the first three seconds, the very fastest anything would have been moving (acceloration = 9.81) is 29.4 m/s, and i should point out thats with no resistance (somehow ). That means it has fallen just 44 metres, making it very hard to explain how this huge cloud of dust which engulfs the building is actually produced at this early stage. The actual speeds involved should not be enough to significantly break concrete, or fireproofing, at all; yet the building completely disappears into this cloud.

(sorry for English spelling of metres, if that annoys anyone )



[edit on 12-12-2007 by ZeuZZ]

Originally posted by ZeuZZ

Originally posted by coughymachine
Here's a pretty good video showing what looks to me like the continuing tilting/rotation of the upper section. The onset of the collapse occurs around 1:58. Watch as the fabric of the building itself disappears into the debris cloud. The cloud swells at the point where the building would be predicted to be, almost embossed.

[
That is a very good angle to see the initial toppling, thanks for posting that one. Its just a shame that you can only see the side corner of the building through amount of dust. Thats another thing, there is no way that the dust would have been that fine and dispersed without there being a very large amount of energy there.

Think about it, if you drop a concrete brick, say from 200 metres, it will certainly smash on impact and you get some big parts, lots of pebble sized pieces, and a small fraction of dust; but you definately do not get a dense cloud of smoky texture dust created. Early in the collapse, say the first three seconds, the very fastest anything would have been moving (acceloration = 9.81) is 29.4 m/s, and i should point out thats with no resistance (somehow

). That means it has fallen just 44 metres, making it very hard to explain how this huge cloud of dust which engulfs the building is actually produced at this early stage. The actual speeds involved should not be enough to significantly break concrete, or fireproofing, at all; yet the building completely disappears into this cloud.

(sorry for English spelling of metres, if that annoys anyone :roll

Actually, I think that video shows the incorrectness of your illustration.

Watch it again and notice what the left side does. It rotates INSIDE the building, since the side we don't see - probably edited out - was acting as the hinge point, meaning that the cog never really moved laterally very much at all.

Your illustration has the top portion sliding horizontally on the bottom piece. Now, I don't know what you propose would have the kind of force to do that in a way that would prevent the top piece from collapsing straight down once the columns weren't aligned anymore, but I'd like to hear.......

Originally posted by scientist

Originally posted by ZeuZZ
7. Horizontal Ejections: But gravitational energy is, of course, vertical, so it cannot even begin to explain these horizontal ejections.

i agree with many of these points, but this one just seems wrong. i can't see how that is valid. Imagine a toothpick, pointing straight up. if you push down on it, it will bend a little. push harder, it will break, and splinters will fly out horizontally. wouldn't this be the same effect with a building?

No it wouldn't be the same. Unless of course Alah was pushing down on the top of the building with his thumb... If you took the tooth pick and sliced a bit off the top and let it drop down on itself you won't get splinters flying anywhere.

Also to answer another myth mentioned in this thread, the top of the towers could not have had enough energy or weight to crush the floors bellow. The building was designed to hold 5x it's weight. There would have been no free-fall of the top section onto the lower undamaged section, unless all the columns were severed at the same time. We only have NISTS theory as far as how many central columns were severed by the plane. Common sense, and some engineering experience, tell me the plane wouldn't have actually severed ANY core columns. Also common sense tells us the fire could not have got hot enough to cause global failure of all that steel.
It might seem 'to make sense' to the uninformed, but if you know how fire and fuel acts then you'd know it's impossible to get office furniture, even doused in fuel, to burn hot enough to cause steel to fail.

For the top section to have tilted as it did, then the lower section would have to be able to hold the weight, as it did. If it was prone to failure, and no longer able to hold it's weight due to heated up columns, the top would not have tilted as it did to start with. Also if the bottom did naturally fail and start to collapse from the weight of the tilting top, the top should have still continued to tilt and slide off unless the pivot point fell faster than the top was falling; how does the bottom collapse faster than the top when it's supposed to be the top causing the failure? (I might not be explaining this well be instead of reacting just think about it for awhile)

Also the theory of floors crushing floors leaves the problem of the central core. If the floors were disconnecting from the spandrel plates then what pulled the central core down?
However you look it this there is problems, but add explosives and the mystery is easily explainable.

Another thing that should make you question is lack of floor pans in the rubble. Where did they go if the floors were the cause of the collapse? We should see a stack of floor pans on top of each other, but no they were destroyed. Now what could do that, gravity?...

The world is perfect. There is no crime. Everybody move along.

PS

The planning that went into 9-11 and the outcomes of it are well underway. The government was not responsible for the attacks and yes most of its employees are incompetent.

Countries died when corporations and money consumed the world. We don't travel on boats for months to stick flags in land to claim it anymore. Business is instant, global and ruthless. Money is King and its empire is the globe.

The people who were behind 9-11 and all the shady dealings of the world are completely competent, THAT IS WHY THEY RUN THE WORLD. People are too stupid or scared to stop them and are brainwashed to think the government is looking out for the people's best interest (they are incompetent, remember?).

The people that created law, government, money, banking and religion own you. The sooner you realize that you are essentially livestock the sooner you will realize that you are expendable.

6,000,000,000 people are on this planet. For some sick people that is way too many and their plans for the world do not include them.

PPS

People that can't understand the why and how of 9-11 remind me of a fundamentalist Christian being explained why the Earth is more than 6,000 years old. Their book of reference is full of errors but since it the word of their authority figure it is infallible and they will make any attempt to defend their beliefs rather than face humility.

...Say it ain't so, Paw.

reply to post by darkbluesky


Thats actually quite a good drawing, and the angle you have it at (to the vertical) is roughly 30 degrees, only slightly more than the 23 degrees which was the final angle that was actually seen before it vanished into the dust. Thats the anlge that top physics proffessor David L Griscom has used for his calcualtions, and he's not going to be using some arbitrary number, he is one of the worlds top physicists. (In full; Ph.D. in Physics, Fellow, American Physical Society, Research physicist at Naval Research Laboratory (NRL), Washington, DC, Officially credited with largest number of papers (5) by any author on list of 100 most cited articles authored at NRL between 1973 and 1988. 185 total articles now in print. Adjunct Professor of Materials Science & Engineering, University of Arizona 2004-2005.)
www.journalof911studies.com...


I have added another few time frames onto your diagram which does well to illustrate the point i am making. I have extrapolated the collapse, the blue arrows are the forces that you added, which are correct, and the ones in red are the ones that I added. Ideally you would not have to break the force into two components, you would beable to draw the resultant force at each time, but since i dont have a graphical drawing program i left them in the same plane that you drew. I also roughly scaled the arrows, so a long arrow means a big force, and a small one a small force.

However, i must first point out that this diagram has no relation to reality, what-so-ever, I am just using the undisputable fact (from hundreds of video's) that the building starts to tip, so the centre of gravity is displaced from the centre. This is to demonstrate what would happen to the top section if the building below was providing no resistance AT ALL after this tiliting motion. And no resistance to the collapse is clearly not what would have happened in the real world.

The centre of gravity has moved from its original position to a position down and to the right, so if there are no extra forces acting on it, it will carry on this path in the shape of a perabola. Even by doing this and completely ignoring the building below, the top section should still land outside the building. This makes it very hard to explain what crushed the rest of the structure flat to the floor.




The gravitational force stays constant for every position, and the velocity component decreases with time. It will clearly should land outside the building. What crushed the rest of the structure to the floor? there had to be some extra energy to do that, as the top section would definately not have done it landing wher it did.

So even with the ridiculous claim that there was no resistance, the tipping motion proves that it should have falled outside the structure anyway.

I will draw another diagram to demonstrate clearly why the momentum has to create a rotational force, and i'll add some maths in too. Bear with me....

[edit on 12-12-2007 by ZeuZZ]

The red area is the section over hanging the building, and i have marked the opposing equal section. Although the lengths are not to exact scale, the angles are, and it is ready for people to put in any numbers they want to calculate the moment of force at any given time, about the centre of gravity of the top section, using any angle or length for the variables, or whatever resistance you want to. However, it soon becomes apparent that no matter what numbers you put in, it will result in rotational motion, pushing the top section outside of the building. Even with the ridiculous claim that having little resistance is normal when a building collapses, the weight of the overhanging section displaces the centre of gravity, and produces rotational torque no matter what.

For the sake or argument i have reduced the angle from 23 degrees to 20, so there can be no dispute that the buildings were seen at tilting at this angle.

F1 is the force due to gravity of the overhanging section (red section), F2 is the vertical componet of the resistive force, F3 is the force due to gravity of the top section.





Moment = Magnitude of Force × Perpendicular distance to the pivot (Fd) - i'll put some numbers in tomorrow when i have more time.

Theres really no need for me to even add the lengths and forces and do the maths, the result can only be rotation. The force on the left can only act up, and the force on the right can only act down, creating clockwise motion.

The resisitive force should be enough to stop any significant downwards movement in the first place. If the resisitve force became greater, this will increase F2 in the momentum diagram, this will reuslt in more turning force and less of the building being damaged due to the building falling outside of the original structure far quicker, and landing further outside. This is what should have happened as buildings are designed to hold up at least five times their own weight, and the twin towers especially, so they could withstand hurricanes and other forces acting on them.



The top section should have toppled over and left most of the bottom half of the structure intact and standing. Period.


[edit on 12-12-2007 by ZeuZZ]

Originally posted by ZeuZZ
(cont)

A lot of the dust you saw was drywall and spray-on fireproofing. Some was concrete, but the majority was your standard drywall (sheetrock) and spray-on fireproofing.

So what? You would still need sufficient energy to break the ‘drywall and spray-on fireproofing’ so you point is irrelevant.

ZeuZZ,

Bravo. And thanks for the clear posts.

It’s pretty clear from aftermath photos that there was no 30’+ monolith pancake, nor debris field of intact flooring period. The simple math of Floor number X’s area and depth of pour, says we should see a mass of “pretty resilient” concrete at ground zero which by pure observation was not there – nor found in the basement for that matter.

Plain and simple the nyc911 “DUST” was largely particularized concrete flooring.

Originally posted by SantaClaus
I hope this hasn't been brought up yet, I only scanned the second page.

My only questions left about this situation are:

How could they have timed the full collapse right with the top floors giving out? Even in CD 's switches are very delayed.

Also, is it possible that large buildings like this have pre-installed bombs in the supports so that when the structure is compromised they blow to limit devastation of the rest of the city? I mean, with gov't structures I could see this being a consideration, and I don't think anyone can watch B7 fall without thinking it was controlled. Its obvious.

Other than that, I was completely unimpressed by all the data until recently, when I began reading the stuff. There are plenty more pieces of empirical evidence showing a controlled demolition than a couple of planes destroying three buildings probably millions of times larger.

Sorry to push this,, but I really would like someone to talk about the above questions. Also, you talk about all this pulverized concrete... In even a controlled demo, wouldn't there still be large chunks? I don't know, just want some input.

Originally posted by SantaClaus
How could they have timed the full collapse right with the top floors giving out? Even in CD 's switches are very delayed.

i think that nowadays they could use instant wiring for whatever was used, so a delay would be unlikely.

Originally posted by SantaClaus
Also, is it possible that large buildings like this have pre-installed bombs in the supports so that when the structure is compromised they blow to limit devastation of the rest of the city?

I think that is a very real possibility, the circuit to put the bombs onto may have already been there in the struture (the electrics were owned by Jed Bush, George Bush's brother) so it would only take a day or two to fit the bombs in place. By taking out the main supports it would casue little damage to surrounding buildings. Though i dont think they expected to see the large amount of horizontal ejections that did actually slightly damage the surrounding buildings.

Also, you talk about all this pulverized concrete... In even a controlled demo, wouldn't there still be large chunks? I don't know, just want some input.

Yes, your quite right, that shows that there was a heck of a lot of energy used what ever happened, far more than even your typical controlled demolition. Whoever did it probably wanted to make absolutely sure it would collapse by putting loads in. What they used to create this energy is a different issue. If you look at the rubble there are hardly any large bits of concrete, and there certainly should be some, at least.

[edit on 12-12-2007 by ZeuZZ]

reply to post by ZeuZZ


Great points. Thanks for the info. But what I meant about pre-placed bombs, is it possible that the bombs were there at building time to limit destruction to other parts of the city? I mean, it would make sense to me, that if I'm building very tall building right beside each other, i would place charges on each floor so that if one falls, it doesn't hurt my other investments. Or are the explosives too volatile, or would they break down over time?

Just being devils advocate and offering a less-sinister CD theory.

Originally posted by ZeuZZ
If you look at the rubble there are hardly any large bits of concrete, and there certainly should be some, at least.

[edit on 12-12-2007 by ZeuZZ]

Agreed. Maybe a demo/explosive expert could correct the record and say floor particularization is no problem. A common ATS theme is a form of destructive beam weapon from on high. I can not comment much on that either.

I have often thought what if my team went in the weeks before with new carpets containing a thin layer of plastic/chemical explosive in the matting. Or we possibly introduce explosives through the sprinklers onto the existing floors prior to ignition.

Sorry - back to your conservation of momentum OP – an excellent hard cold fact.

reply to post by ZeuZZ


ZeuZZ, that was an excellent explanation. I contacted Dr. Jones last year, regarding what I labeled the Leaning South Tower of Pisa. Dr. Jones replied they had not actually done much investigation due to the complex nature of proving controlled demolitions were used. He stated he would be doing more study on the laws of physics defying feat (per the "official" version) of the South Tower. Obviously, he kept his word on that.

There should be no question that controlled implosive demolition techniques were used. It is so obvious by all the most basic classic and quantum physics information available. The structure of the core is a dead giveaway that no plane and kerosene would bring down any of the WTC buildings. Only controlled demolitions can turn buildings into rubble in their own footprints. That is a law of physics given.

A study of the Empire State Building, when it was hit by a miliatry plane, will give excellent insight into what planes, slamming into concrete and steel buildings, are capable of doing to the buildings and planes. Yes, there was an hours long raging fire in the Empire State Building, which we should all know remained standing after being slammed by a military plane. The WTC buildings were built to withstand the impact and fire from a commericial 707.

As for the rudeness of some people toward your educated post, it is best to ignore such discourteous people. They either deliberately keep themselves uneducated or are plants to discourage people from learning the truth about 9/11. The families, of the victims of 9/11, definitely deserve to know the truth of what actually did happen on 9/11. The US bureacracy owes them the truth. We, the people (the true government of the US), have an obligation to this country to ensure they receive the justice and truth they and we deserve.