Thanks for the reply and informing me that I did not supply all of the necessary parameters.

In this case, no time. It has to go from 0 to 50 mph instantly (as if propelled by an explosion).

Hi bhrescobar,

Nice explanation here.

GA to you Sir.

Take care

Thanks. The question arose from looking at a videos of WTC 1 collapsing and a video called "4 Ton Girders: Blowing in the Wind?" seen on YouTube which calculates of the speed necessary to make 8000 lbs move laterally 600 feet from the height of the blast that propelled it to the place it landed. So your answer with regards to "instant" describes a very high transfer of energy. Since this was part of a building that was falling at close to free fall speed, the law of conservation of energy would have to have been violated, and since that is not possible some other energy source (other than the the weight of the building being transferred to kinetic energy) must have been available. Since neither the 9/11 Commisson report nor NIST reported on that, what that energy source was is a matter of speculation.

You're welcome!

Can you provide links, so we can see what you are referring to?

YouTube video:

4-Ton Girders: Blowing in the Wind? http://www.youtube.com/watch?v=aUKLOlIhang&feature=player_embedded

provides physics demonstration about ejection of 4 ton girder found 600 ft to the West of the WTC 1 found on roof of Winter Garden on 9/11.

Youtube video 9/11 Audio Tapes http://www.youtube.com/watch?v=RqLQLBWaDRE&feature=related at about 3:20 clearly shows the North tower ejecting steel on to the roof of the Winter Garden.

Unless an object has a means of propulsion pushing it down, it cannot fall faster than gravitational acceleration. This knowledge of basic High School physics is enough to prove that the official explanation can not be squared with the speed of the three building collapses or the plumes of dust observed on 9/11.

Newton's law of gravity tells us exactly what to expect from falling bodies. A falling object experiences a constant acceleration of 32ft/sec squared. We can calculate that the time it would take for an object to fall from the top of one of the 1350ft WTC towers is 9.2 seconds without accounting for air resistance. When air resistance is included, for example, for a brick falling from that height would be expected to take about 12 sec. This is very close to the approximately 10 seconds it took for the towers to fall as reported in the official 9/11 Commission report or the 13 to 15 seconds as independently measured from observation of various videos of the collapses. The towers fell at essentially free fall speed. Another fundamental law of physics is the conservation of energy and it applies to falling bodies as well. An object, as it falls, converts its gravitational potential energy (weight at height above ground) into kinetic energy (motion). If that object has to use some of its energy for something else, like pushing air out of the way, or turning material into dust, then there will be less energy available as kinetic energy so it will take longer to reach the ground. As we've seen in the example of a brick falling from the top of the tower, even the energy required to move air out of the way is enough to slow the free fall time from 9.2 seconds to 12 seconds.

In the "official" explanation of the collapse, to the extent there is one, the floor above gives way and crashes into the floor below it, which gives way and together they fall on the next floor below, and so on. The falling floor must use a considerable amount of its energy to break loose the floor below. In addition, to account for the observed dust plumes, the crashing together of the floors has to crush the concrete floor slabs into a fine powder. That takes a substantial amount of energy. Additional energy is also required to eject those tons of crushed concrete and steel at high speed in all directions because that's what was observed on 9/11 (a 4 ton girder section of WTC 1 was found 600' to the West on the roof of the Winter Garden). All of this energy must be subtracted from the original potential energy of the falling floor, which means there is much less energy available as kinetic energy (motion) so the floors must be falling much slower than they would otherwise.

How much slower? I don't have to be an engineer to realize that the energy required to crush concrete into fine powder and blow it out of the buildings at high speed is many times more energy than is required just to move air out of the way; perhaps hundreds or thousands of times as much. If the energy required to move air out of the way of a falling brick could increase the fall time from 9.2 sec. to 12 sec, then the requirement to not only move air, but also crush concrete, and eject tons of crushed concrete dust and large steel sections laterally at high speed, should have increased the fall time considerably, but it didn't. The fact that the buildings were observed to fall at essentially free fall speed, means that all of the gravitational potential energy of the building was in fact converted to the kinetic energy of falling. The fall speed accounts for all of the gravitational potential energy available.

There should have been no gravitational energy left to break steel, crush concrete, eject dust or do anything else but just fall. The Law of Conservation of Energy forces us to conclude that there had to be some additional source of energy. Some source of energy to pulverize the concrete and send it in all directions, at high speed as a fine powder. Additional energy was required to break welded steel sections free and eject them from the building (the four ton section that landed 600' away on the roof of the Winter Garden had to accelerate to over 50 MPH to get there from the height it fell, and it takes a lot of energy to make four tons go from 0 to 50 MPH, not to mention breaking the section free from the other girders to which it was attached). Some additional energy was required to knock out the heavy steel beams that had supported the building for 40 years so that the top of the building could free fall, unimpeded, to the ground in just over 10 seconds.

What was the source of the additional energy? I don't know. Since the 9/11 Commission and NIST neglected to investigate that, it has been left to our imagination. Clearly we need a new and independent investigation of what really happened on 9/11/2001 because the official explanation does not pass a basic High School physics test.

Hi devo,

GA here for a good explanation, OK.

Take care.

Conservation of energy isn't violated.

Atomic bomb

There is no evidence of an atomic bomb. Is it possible that a fourth generation thermonuclear device that does not require an underlying fission bomb was used, but unless I had some very solid evidence to back up that claim, I would not assert it.

got my shades on just incase

Hi madness,

Please behave!

Even the smallest Atomic bomb would have been a lot more obvious and would have flattened a substantial part of the City.

Slap on the wrist for you mister!

Take care.

Tee hee hee couldn't resist that one.

good to chat again, do wish i had more time here

Take care

Hi bhrescobar,

I like your advice to stick to SI units!

GA to you Sir.

Take care.

Does the statement" conservation of energy" refer to an action in a closed system? The final moments of the structure during the destruction of the World Trade center towers involved a tremendous amount of distinct components, sub-structures, liquids, gases, and yes, sadly, human beings violently interacting. I don't see how this could be accurately modeled in order to provide an exact reconstruction and prediction of the behaviour of EACH and Every component. Results from modeling can have enormous differences in results from introducing small variables in the sequence. There might be a cause that is not readily visible in the video simply because of the recording angle or limited field of view. If you can access a copy , read Mario Salvadori's book, " Why things fall down." Just as an example, in researching and involvement in a hands on way in the area of terminal ballistics, I have found that projectiles and targets can behave in astonishingly counter-intuitive ways.

See comment #9.

Conservation of energy applies to all falling bodies: as an object drops it slows down as it interacts with anything. If you had read one of my earliest posts, you would have seen that a brick falling from the top of one of the trade towers would have taken 9.2 seconds in a vacuum, and 12 seconds in air. If air resistance can slow a brick down that much, then turning concrete, computers, people, telephones, walls, furniture etc. into dust and ejecting that dust would slow the fall far more than air resistance. You don't have to model for each and every item to understand the concept: all you have to do is understand that as potential energy is transferred to kinetic energy no energy is created, it is just changed in form. The videos of the collapses of the trade towers were taken from quite a number of angles, and the timing on the collapses varies from 10 sec. in the 9/11 Commission report (very close to the 9.2 seconds of falling in a vacuum) to observable times of 12-15 seconds in the videos (very close to free fall in air).

Hi packrat,

The "reconstruction" I mention was with respect to how the aircraft entered the building and the known damage it did on that single, or two or three floors.

It did not involve, nor could it have done, the whole destruction sequence of the Towers falling.

Take care

HI b-bear, that makes sense.

http://wtc7lies.googlepages.com/wtccoreconstruction

Here's a page that shows the WTC towers under construction. While the video shows the core, I don't think it accurately represented how much steel was in it.

If you're willing to wait 2.28 seconds you don't need to add any energy. Just drop it off a cliff!

Looked at the two videos indicated in the above post. I'm no engineer, but i do know that steel is an extremely elastic material. Maybe the mysterious laterally traveling steel beam had, at impact a load placed on it that was enough off of its centerline to cause it to momentarily compress , then rebound perpendicular to the load. Like when you hit a greasy 10d finish nail with a ball peen hammer (source: Brother Dave) or if one were to try and compress a nail placed lengthwise in the jaws of a pair of pliers.

I'm waiting for the other shoe to drop as regards the implications of this beam apparently violating the laws of physics; black helicopters? a brokerage firm storing large amounts of high-brissance explosive with the copier toner? Space Robots? Mossad? CIA? C'mon spill it, ya know you want to.

It could only be done by a conspiracy of the government in partnership with the space aliens in Area 51 and hidden in the underground facilities in the Four-Corners region......

osborne ! Remember the First rule of Nazi Zombie CIA Space Robot Club...

To those who want to engage in sarcasm instead of an informational discussion:

Why don't the folks at CDI and other demolition companies should use Kerosene and ordinary office furniture to bring down buildings? Based on the collapses of the WTC towers and 7 WTC this would make the process faster, more cost effective and much safer.

1. It's much faster. Instead of taking weeks and months to wire a building to be demolished, you just light a fire and let it burn for 7 hours or so and TA DA, the building collapses!

2. It's a lot safer to deal with kerosene because you can put that fire out, but if C-4 or detonator cord is touched off, boom!

3. 100% Success rate! 3 incidents 3 successful collapses! How do you beat that? I doubt the industry has a 100% success rate using explosives.

4. Savings! I could be wrong, but C-4, thermite cutter charges or whatever explosive is used and weeks of man hours is probably much higher than kerosene and office furniture. Sorry I can't support that cost analysis with any data, but I doubt that getting Abdul the gas pumper to pour the fuel into the building is more expensive than engineers who plan out how to bring the building down into its own footprint.

5. Once collapsed, the debris removal would be much easier as most of the material will be turned to dust and evaporated!

6. Uh oh, there is a problem. They would have to hang very large nets from the top of the building to catch the tons of material that is ejected horizontally into the air. That way it should minimize collateral damage to surrounding structures. Again though, its still probably much cheaper than labor and explosive material.

7. They could fill the basements of said buildings with lots of water (very cheap!) before lighting the fires, that way pools of molten metal wouldn't hamper the debris removal like they did at the WTC.

This concludes the new way for Demolition Companies to bring buildings down. I hope to see enacted shortly for the sake of cost and safety to the industry.

see both 14 & 15

The 4 ton girder is just one of many unexplained anomalies. How did a gravitational collapse create a dust cloud that made lower Manhattan look like nuclear winter while it was falling at near free fall speed? All of the energy at gravitational acceleration is used up in falling, there is none left to break up concrete, furniture, interior walls, computers, people, etc. So the fact that a four ton girder was able to break free from the other girders supporting it and accelerate to over 50 MPH has to have a source of energy other than the falling building, or that act alone would have significantly slowed the collapse.

The final NIST report on the collapse of 7 WTC (NCSTAR 1A.pdf), the third building that fell that day, states that it collapsed because of fires from ordinary office furniture. It also states in the last paragraph on page 48: "(2) a freefall descent over approximately eight stories at gravitational acceleration for approximately 2.25 s" which considering that the building was a 47 story skyscraper would make that the first and only collapse at that speed from fires. The building collapsed evenly, even though the fires were not uniform over the entire structure. How could those fires remove eight floors of building material simultaneously so that the building could fall at that rate of speed?

Aside from the cutting wire analogy above you have the shattering of piles phenomena, (in pile driving when a pile hits a solid resistance) It is quite conceivable a column remnant shattered after being driven through a falling floor slab, or an exterior column shattered. This would give the 'distance'.

There is no sign of explosives in any video. No need for explosives in this collapse. Both relate directly to how much mass was above the fire, the number of floors affected by fire (so how big the first fall distance/energy).

It is more remarkable that the more or less intact top floors did not shatter more when they stopped falling.

Thank you

No signs of explosives in any video? Really now! Is denial a river in Egypt? Three buildings fell symmetrically at close to freefall (gravitational acceleration) due to fires? The impacts from the planes in two out of the three buildings were asymmetrical, but the collapses of the two towers were symmetrical, and other than the initiation sequence of 2 WTC and 1 WTC, were virtually identical in appearance. The debris field from the Twin Towers collapses sent girders hundreds of feet, yet they fell at nearly freefall speed. The conversion of potential energy to kinetic energy means that when an object moves from rest to falling, it can only fall at the rate of gravitational acceleration minus air resistance unless it has propulsion behind it. Any other interaction it has must slow its descent down. Here's a first hand demonstration you can try: dive from a 10 meter platform with nothing other than the pool below you, you will get there faster (and less painfully) than if you have to break a pane of glass between you and the pool.

Below are but a few of the videos that show signs of explosions.

WTC 7 Explosion on Audio (heard by firemen)http://www.youtube.com/watch?v=0YvrKfWkxdw

"Keep your eye on that building, it'll be coming down soon." http://www.youtube.com/watch?v=z9CXQY-bZn4

Explosions on 911 http://www.youtube.com/watch?v=CcRs1fv8i3I

9/11 Revisited: Were explosives used? http://www.youtube.com/watch?v=PWgSaBT9hNU

EXPLOSIVE TESTIMONY! / MacQueen NYFD 9/11 witnesses http://www.youtube.com/watch?v=cZ4dVo5QgYg

9-11 INSIDE JOB ! WTC 7 Controlled Demolition side by side ! http://www.youtube.com/watch?v=sCMk59ndhcg&feature=PlayList&p=14AA7BE54D7C310A&playnext=1&playnext_from=PL&index=55

9/11 CONSPIRACY: FBI REPORTED CAR BOMB IN THE BASEMENT http://www.youtube.com/watch?v=SGE6GNKNpPA&feature=PlayList&p=14AA7BE54D7C310A&index=56&playnext=2&playnext_from=PL

911 WTC DEMOLITION SEQUENCE FINALLY REVEALED http://www.youtube.com/watch?v=IX9gdRST6zM

9/11: Molten Metal at Ground Zero http://www.youtube.com/watch?v=cCdRA09pztM

What was left of the top floors? What was left at the bottom of ground zero under the twin towers?

Then there is 7 WTC: NIST admitted that eight stories of that building fell at the rate of gravitational acceleration. How is it possible that asymmetrical fires can remove eight stories of building material from a modern steel framed skyscraper symmetrically?

"Three buildings fell symmetrically at close to freefall (gravitational acceleration) due to fires?"

The short answer is yes.

To make a building fall asymmetrically is quite difficult and highly skilled. It requires an active "hinge", much as felling a tree, or a lateral sequential collapse to 'pull' a remnant in a desired direction. E.g. http://www.youtube.com/watch?v=oZ-L1aHFS4U&feature=fvw

http://www.youtube.com/watch?v=oZ-L1aHFS4U&feature=fvw

http://www.youtube.com/watch?v=oZ-L1aHFS4U&feature=fvw

Get it wrong and fascinating things happen;

http://www.youtube.com/watch?v=g7z-FQUrfhc&feature=channel

There is no "river in Egypt" about this, except among "Myth-buster level understanding" of propagation rates and idiot theorists extrapolating on 'possibilities' based in "no practical experience".

The velocity (propagation rate) of explosives is remarkably visible to the experienced and significantly different in appearance to self destruction from even 'extreme ' compression or shock.

Admittedly both Fire and demolition industry practitioner have found 9/11 fascinating in the impact of such a large volume of accelerant and the mechanics of the collapse - but bottom line is the masses and mechanics behaved in a totally predictable manner in response to 'removal' of the structural integrity of one or more floors.

And that removal was undeniably due to the introduction of a huge volume of accelerant.

Look particularly at plane 2's banked impact and the accelerant spread that occurred and mass above.

How much 'hinging' can occur in a meaningful time line under such a huge down force? The highly technical and professional answer = Fu*k All.

If the answer is yes, why do CDI and other demolition companies spend so much time engineering buildings to fall symmetrically? Why don't they just take the route I pointed out in post #15 and use kerosene and office furniture to bring buildings down?

The fact is that it is very difficult to make a modern skyscraper fall symmetrically because of fires. As a matter of fact, prior to 9/11 this had never happened to a modern steel framed skyscraper anywhere in the world.

But I am glad you pointed out the active "hinge" because WTC 2 (the South Tower, second building hit, the first to fall) started falling over the asymmetrical cut in the building created by the crash that came in heading NNE. It hit closer to the corner of the building, and its crash created a huge fireball both on the East and North Sides of the building and a smaller fireball at its point of entry. As WTC 2 started to fall, it tilted over the "hinge" then it did something that defied the law of angular momentum: it did not continue to to travel in the same path that it started. Instead, it turned to powder in mid air. One of the best videos of this is:

9/11 - WTC 2 - South Tower Collapse http://www.youtube.com/watch?v=lTutneLXup0

A detailed description of what happened to WTC 2 can be seen at http://911research.wtc7.net/wtc/attack/wtc2.html

It is highly unlikely that all of the structural material in any one of the floors was damaged uniformly.

As to the amount of accelerant: the fireball(s) seen when the South Tower was hit would account for a significant amount of the jet fuel. NIST stated that the diesel fuel stored in 7 WTC was not a significant factor: the fires that brought that building down were from ordinary office furniture and paper. The North Tower took longer to fall than the South Tower, even though it had more unaccountable accelerant.

The short answer is yes.

How come it never happened elsewhere before or after 9/11?

It is quite naive to think that. Most of the aircraft fuel was gone in short order. The towers would never ever have come down without explosive charges after plane impact, that is so clearly visible.

What about the molten steel in the basement? where would that energy come from if not from explosives?

Does your last observation not tell you something? That is because up there were no explosive charges laid.

You say nowhere are explosions visible. How can you say that when the explosions can be so clearly seen. You must train your eye to that.

Also why where no investigations made at the site before rubbish was removed? I know for a fact that Canadian fire fighter asked to come down and help. That help was strictly refused. When some arrived at Ground Zero anyway, they were denied access. Simply because they may have been able to "see" something may be a realistic conclusion.

Bob:

My brother was a volunteer fire chief at the time of 9/11. He almost drove from where he lives to NYC until the Towers collapsed.

I appreciate firemen and the service they provide. There is a group of firemen who have started speaking out about what they heard and saw on 9/11: http://firefightersfor911truth.org/

and the following is copied from the above site:

An Appeal to Firefighters, Present and Past

Fellow Firefighters, A great tragedy befell our community on September 11, 2001, an unprecedented 343 deaths in the line of duty. As horrible as that toll is, if there were a rational explanation for it, we could accept it and mourn. We all understood the risk we accepted when we took the oath of office, that chance might cut short our lives when we placed ourselves in harm's way in the public's service. This is what we are paid for and it is our honor. However, in short, the official explanation of the events of that day are not only insufficient, they are fantastic and cannot bear rational examination. We are asked to believe that on that day three structural steel buildings, which have never before in history collapsed because of fire, fell neatly into their basements at the speed of gravity, their concrete reduced to dust. We are asked to believe that jet fuel (kerosene) can melt steel. We are asked to believe that the most sophisticated air defense system in the world, that responded to sixty-eight emergencies in the year prior to 9-11 in less than twenty minutes allowed aircraft to wander about for up to an hour and a half. We are asked to believe that the steel and titanium components of an aircraft that supposedly hit the Pentagon "evaporated". There is much, much more if anyone cares to look into it. Trade Tower #7 by itself is the "smoking gun". Not hit by an aircraft, with only a few relatively small fires, it came down in a classic crimp and implosion, going straight into its basement, something only very precise demolition can accomplish, which takes days if not weeks to prepare. The 9-11 Commission actually stated the they DIDN'T KNOW WHY IT COLLAPSED AND LEFT IT AT THAT. Brothers, I know that the implications of the above are hard, almost unthinkable, but the official explanation is utter nonsense, and three hundred and forty three murdered brothers are crying out for justice. Demand a genuine investigation into the events of September 11!

-Anton Vodvarka, Lt. FDNY (ret)

Hi bob c,

Nice to here your thoughts as a Fireman, thanks.

GA to you Sir.

Take care

Thanks for the reply, but I am a maintenance tech for the fire dept.

Thanks. I have seen that simulation before. The Purdue simulation was designed only to create a realistic visualization of the 767 colliding with the Tower. It did not assess structural damage or model how the ensuing fires supposedly led to the total destruction of the building 102 minutes later.

The plane entered WTC 1 came from North. The plane that hit WTC 2 came from South heading NE. The 4 ton girder section was from an exterior wall on the West side of the building. It was clearly not a result of either aircraft hitting the building. Youtube video 9/11 Audio Tapes http://www.youtube.com/watch?v=RqLQLBWaDRE&feature=related at about 3:20 clearly shows the North tower ejecting steel on to the roof of the Winter Garden, across West Street from the WTC complex.

Hi devo,

I thought I told you that the metal girder had been ejected?

I may have gotten the direction of the aircraft wrong, and I am sorry for that but otherwise I agree with all you say.

You did not comment on my idea of the WTC falling quicker if you count from the 96th, where the aircraft hit floor rather than the 110th top floor.

For what it is worth, I do not think fire was the main cause of the structure failing.

I think it is a simple case of 'pan-caking' floors from the 96th down. One floor plus the effective 'bomb, (the aircraft) entering the building, collapsing and on down .

I have to say this though; considering it was a 'modern' building, there was a tremendous amount of carcinogenic materials used in it. I can see no reason for that, other protection should have been used................ Cost cutting again?

That building, as does others, has a 'limited life span', where it would then need to be taken down. There would be a huge risk of dangerous materials escaping into the air of the City.

I just wonder;................. What about the other really tall buildings around the world, perhaps it is time they are checked and double checked for inconsistent concrete quality across each of the enormous floors involved? There is no way a guarantee can be made this will NOT be happening again ANYWHERE, and with other buildings twice the height, or heading that way, of the WTC it could easily involve a substantially sized 'chunk' (technical term you may not be familiar with) will, or could be wiped out.

I am on your side. But am not sure at all, that the WTC's fiive structures were brought down maliciously.

Three of the smaller, though still substantial structures, were extremely damaged but, never came down. If there was a malicious reason involved, say Insurance, as these buildings, which cost just a few million Dollars to build, were insured for several Billion Dollars! I am open to be advised otherwise, but am pretty sure this is so.

Another worry is the WTC 7 being brought down just a matter of hours (I think) after the aircraft hit the taller towers. WTC 7 was out of the 'square', where the main WTC buildings are or were. WTC 7 was built with the 'square' in front, and a building either side, with the WTC 7 and these other two building forming a straight edge of a series of buildings. Why was WTC 7 taken down, with I presume explosives, when the building either side of it could have had the same or worse damage but, stood without enough damage to be demolished? Very odd that?

Take care.

Hi Babybear,

Thanks for agreeing with me. I appreciate that. If you want more info on this go to:

9/11 Speak Out http://www.911speakout.org/

Architects & Engineers for 9/11 Truth http://www.ae911truth.org/

(to date,

907 architectural and engineering professionals and 5062 other supporters including A&E students have signed the petition demanding of Congress a truly independent investigation.)

and or

9-11 Research http://911research.wtc7.net/index.html

I did not comment on the WTC falling quicker if counted from the 96th floor because the North Tower survived for 102 minutes after the plane hit. Using your idea, the South tower should be counted from a much lower floor, but it lasted 56 minutes after being hit. Since the top of the tower was still in place in both instances at the initiation of collapse, the distance they had to fall was unchanged.

The pancaking floor theory would have left a pile of rubble about 1/8 the height of the building. Also, if the floors broke free from their trusses and pancaked, why would the center core have fallen to the ground with them? After all, it no longer has to support their weight any more, and why would the girder structure around the perimeter of the building blow out in little (and 4 ton) chunks?

One of the Twin Towers had about 400 tons of asbestos in it. They stopped using asbestos part way through the construction project, but it would have been very expensive to deal with that. Outside of that I don't have enough information to comment further.

7 WTC came down at 5:20 p.m. It had been hit by debris from the demise of 1 WTC, and had fires on several floors. The fire department had withdrawn from it quite some time before its collapse: apparently there were problems with water supply to fight the fires. The fact that it fell symmetrically, nearly within its own footprint, in somewhere between 6.6 to 7 seconds and had a level roof line while falling (with witnesses seeing the bottom blow out first) is very typical of a controlled demolition. How they rigged an occupied building is beyond me.

To those who voted my Post 35 Off Topic:

It goes into a lot of detail about the discussion this thread has turned into, as apposed to the OP.

I would be interested to know why my post was voted off topic.

Take care

I believe it is done as a way to show disagreement with you.

What is odd here? What brought down Tower 7?

You said explosives. OK. Why would that prove that the two big towers were not taken down this way too?

Hi Floram,

With regard to post #39, I say "odd" because the Post Office and Verizon Building were either side of WTC 7, and neither as far as I know were damaged enough to require demolition. Simple as that. At this moment as I type this, I cannot recall exactly when WTC 7 came down but, I know it was several hours afterwards and the owner gave permission to bring it down, in my mind as perhaps it had to come down, and was more than covered by the extra Insurance, which was over and above the original cost of building, to allow a complete rebuild of any building which was called 'WTC', and hence a complete new start when a new build was started.

I do not know if the Post Office and Verizon blocks were part of the same build as the WTC, and so therefore accept any findings or 'guesses' from anyone who say I am talking nonsense. I think perhaps I talk more sense than some of these posts.

Absolutely no insult intended here OK?

Hi Baby bear,

I have no intentions of insulting you or anyone either.

Just facts count. I agree that building 7 was brought down on purpose by explosives. I just wonder, does any building have explosives placed at time of being constructed? How come it was already charged? All that was needed was a nod to bring it down. All demolition explosives were already in place.

Would that not make you think that the other towers were also already charged with explosives, just in case? for what I don't know. But don't you find it odd that building 7 was already placed with explosives. Could the same not have been done with the two big ones?

Just questions I am raising.

Hi Floram,

With all other building which were 'blown' down with explosive, the buildings were cleared, and there was no contents, no pipe, usually no glass, no power of any kind.

With regard to WTC 7; if all that was not a criteria, I imagine you could just send in as many people as there was vertical beams, each with a stick of explosive and it would be done in a matter of minutes?

Of course the same may have happened with the main two Towers. And it would have been relatively easy to do by placing the explosives in the Utility spaces, of which there were four more or less equally spaced every 20/25 floors. But, would not those people planting these explosives have been videoed, or have had to 'sign into the places?

Perhaps in future the 'safety and control Centre with all the TV screens should be in a building several miles away from the building which could potentially be under attack. They (the people who counted the workers in and out) and whom must have been asked "who is in there" etc, must have noticed anyone out of the usual bunch there could have been in that day or week?

Take care.

Hi Babybear:

I don't think you can rig a burning building with demolition charges, so IMHO 7 WTC had to be rigged in advance.

I used to sell IT services. I threw Scott Forbes business card away with tears in my eyes thinking he was dead. " Scott Forbes 9/11 power down: The Elephant In The Room

http://www.youtube.com/watch?v=brSXmZVVCMI

I was outside of the 110th floor of 2 WTC at one point in my career, it was a special engineering area and I was working on a microwave shot. What a view! I remember the barometric vestibule that you had to go through to go outside so you wouldn't get sucked outside by pressure differential. The WTC was engineered very well.

I'm about done, but I can't wait to hear back from MechanicBSME....hehe.

FYI WTC 7 came down at 5:20 p.m., 20 minutes after Jane Standley of the BBC said it collapsed. Pretty amazing to have a reporter accurately report the news in advance, isn't it? You can see 7 WTC in the window behind her as she's talking about a building that has just collapsed. I couldn't make this up if I tried.

BBC Reports Collapse of WTC Building 7 Early-- TWICE http://www.youtube.com/watch?v=6mxFRigYD3s

The Verizon Building was to the West, and the Post Office was to the East of WTC 7.

Larry Silverstein, the leaseholder for the WTC complex and the owner of 7 WTC was seen on a PBS special said:

"I remember getting a call from the, er, fire department commander, telling me that they were not sure they were gonna be able to contain the fire, and I said, 'We've had such terrible loss of life, maybe the smartest thing to do is pull it.' And they made that decision to pull and we watched the building collapse."

"Pull it" could refer to pulling the plug on the operation, or pulling the manpower out, and just letting it consume itself.

Not in the context that Larry Silverstein used it, and the fire department doesn't ask a civilian how to conduct its operation.

Ho devo,

Unless you were inside Mr Silverstein's head as he said what he did about "pulling it" or similar, you cannot fully understand what was said and the full context. As any of Mr Silverstein's video's are edited over and over and could easily have been played back in any order.

Take care

WTC 7 - Pull It By Larry Silverstein http://www.youtube.com/watch?v=7WYdAJQV100

I am not a mind reader, but I do understand context. He didn't say pull them out, he wasn't talking about the firefighting crew: pull it is a demolition term meaning implode the building.

I think I should apply for a job with CDI as their VP of Safety and Cost Control. Since WTC 7 came down because of fires from office furniture (according to NIST and CDI has not disagreed with the NIST report) perhaps they will see that they no longer need shaped cutter charges and complex engineering studies to collapse buildings quickly and safely. No relevant experience needed!

Thank you for providing the video of Larry Silverstein. After watching it I believe that the fire official was trying to break the news to him gently that his building might not make it. The call to stay and fight, or to pull the plug is always made by the senior ranking fire official on the fire location, known as incident commander. After learning that your command staff along with hundreds of firefighters had just been buried in the last two hours, how committed would you be to keep additional personnel in a building that might have been damaged from the collapse debris that rained down on it?

As far as placing explosives in the building, just when do you think that happened? Before the planes hit, while the first building was burning, or did the explosive experts wait until the conversation with Larry Silverstein? That would have sounded something like this:

Ok. I just talked to Larry. He said to blow up the place. Everyone go grab a stick of dynamite and place it on the perimeter beams. Bob, you start connecting them together. Hey, be careful in there, there are fires all over the place from falling crap, and the roof has collapsed in a few places. Lets be careful in there!

In order to rig a building for controlled demolition, you have to spend a significant amount of time engineering it. This had to be done in advance.

The roof of WTC 7 collapsed in a level line with the rest of the building.

Hi Floram,

No.

Take care

"at about 3:20 clearly shows the North tower ejecting steel on to the roof of the Winter Garden, across West Street from the WTC complex."

I watched that video more than once, and many others as well. It clearly shows material being ejected, and that material probably does contain steel, but I see nothing that is clearly steel.

You clearly are convinced that something besides the two planes was involved in causing the collapses, and it appears that nothing will change your mind.

I see nothing in any of the videos that can't be explained with ordinary physics of heat, pressure, gravity, etc.

What can NOT be explained by physics is how these people's religion has such control over them to make them commit such acts!

The fact that the building falls at or very close to the speed of gravitational acceleration while it pulverizes materials, blows them out as dust and ejects steel girders at high speeds (there was an 8000 lb section of WTC 1 on the roof of the Winter Garden) means that forces other than gravitational acceleration from a collapse were involved. The law of conservation of energy applies to falling bodies and collapsing buildings.

How do you explain the extra energy, especially in 2 WTC where most of the jet fuel burned off in the big fireballs?

This is absurd. The mass of steel you keep referring to that was ejected was really a very very very small fraction of the mass of even one floor of that building. Whatever energy it took to eject that beam is negligible when compared against the mass of the falling body.

Yes, your comment sounds absurd.

Where did all the energy come from to bring the buildings down? For sure not from the plane fuel that was burned out in less than a minute. I know you have not watched the 56 Minute video.

Good point.

So Machinist BSME, are you familiar with Newton's law of gravity?

Does it accurately tell us what to expect from falling bodies?

Are you familiar with the law of conservation of energy?

Can a falling object without propulsion travel faster than gravitational acceleration?

Will a falling object's speed be reduced by air resistance (friction) if it is falling in the Earth's atmosphere?

So when an object is falling at or near the speed which is created by gravitational acceleration, can it do anything else without slowing down?

Thanks in advance for copying and pasting the questions and answering all of them in the spaces provided.

"Can a falling object without propulsion travel faster than gravitational acceleration?"

I would think common sense would tell me no, but then again, common sense would tell me that a wind -powered vehicle can't exceed the speed of the ambient wind, but I now know that's not true. Maybe the dieseling combustion of the between floor contents created a negative pressure wave ,thereby accelerating the floors down, similar to the scavenging effect in a tuned, two-stroke exhaust pipe.

Interesting but I think you are grasping at straws to hold on to a myth.

HI Devo,

Which myth?

p-rat

The myth that fires from jet fuel burn so hot that they cause steel framed skyscrapers to collapse at or near freefall speed while grinding everything in them to dust and ejecting copious amounts of material. The myth that fires from ordinary office furniture can cause a 47 story skyscraper to collapse neatly in its own space after burning for only 7 hours.

That report proves absolutely nothing.

Smells of paid propaganda. Sorry Babybear.

Hi Floram,

No need to be sorry my friend!

I think this reconstruction video was as close as it may have been possible to get to what actually happened. And was made to explain what happens over the period of half a second......... a blink of an eye.

I have said I believe in neither the Conspiracy Theory. I am more inclined to believe the usual Physics explanation. Apart from anything else, as this thread and the believers of a Conspiracy Theory have proven by some rather silly examples, each or part of one of those explanations are taken and some other nonsense added to make yet another reason or explanation for whatever?

It is important to stay on 'terra firma' when thinking these things through. Not say something which makes no sense or has no relevance to the WTC at all. Unless of course, there are people who can actually see through all the dust and chaos of the thousands of tons of all that a building that size contains, including furniture and people and the remains of hundreds of tons of aircraft and its contents, some of which are bound to have been explosively combustible.

Take care.

Hi Babybear,

The movie I watched was more like 58 Minutes, not 1/2 second.

http://www.youtube.com/watch?v=PWgSaBT9hNU 58 min,

Just like you, I like to look at facts and not theories. Fact is that the fuel of the jet was burned out very quickly. It did set furniture on these two floor on fire, for sure.

But how much heat can be created by burning furniture? Also, how come that lower floors suddenly burst into flames at an instant and only then, as a result of that, the building started to collapse? Where did these fires com from?

If the building would have collapsed and as a result of that flames and smoke did appear that would make more sense, but the flames and smoke were first and then the collapse started.

How can you scientifically explain the sudden outburst of flames at way lower levels leaving a lot of floor in between untouched by flames or smoke. If you can explain that I would appreciate.

This is just one of many other points leading to the possibility of explosions. BTW many firefighters said that explosions occurred and these can easily be made out and recognized as such in the 58 Min video.

Do you have any explanations for that? I don't, other than that these actually were explosions.

I leave it at that until you watched the video.

Hi Floram:

The fires at 1 WTC smoldered, billowing black smoke the whole time from after impact to collapse. The smoke indicates that the fires were inefficient, oxygen starved and not burning anywhere near as hot as they could have. The big fireball that accompanied the crash at 2 WTC probably burned off most of the jet fuel, but not all of it.

An office fire can reach 1000 degrees F, but since the WTC tower fires burned for less than two hours they would not have been able to transfer much heat to the building structure. On February 13, 1975 WTC 1 had a fire. Details: http://whatreallyhappened.com/WRHARTICLES/wtc_1975_fire.html

Hi Bob:

Thanks for helping prove my point: If the floors pancaked down as the trusses gave way, each floor would have to move the air out of the way, crush all of the material below it and above the next floor before it hit the floor below it, then it would have to slow down as it transfers energy to break the trusses of the floor below it, and repeat the process, right? As the floor blows the air out of the way and pulverizes the concrete, computers, people, interior walls, furniture, computers, telephones and toilets it is using energy to do that, right and it is also using energy to break the floor below it free, isn't it? So then if the falling floor is doing all of that, how can it fall at or even close to the rate it would fall as if it was a brick being dropped from the roof of the WTC? The 9/11 Commission report said one of the towers fell in 10 seconds. A brick falling from 1350 ft. in a vacuum would have hit the ground in 9.2 seconds, the visual observations from the videos of the towers collapsing show they fell between 12 and 15 seconds, very close to the speed which it would have taken for the top floor of the building to fall through the air. So where did all of the extra energy come from that enabled the buildings to fall that fast while doing all of those activities and creating a debris field with structural steel components flung as far as 600 ft away?

Hi bob c,

GA to you Sir for a good explanation.

Take care.

BTW, I had already gotten a GA and other votes to my other posts destroyed it. I give you this which means you also have a real Thumbs UP! I only hope you keep it and not lose it by others voting your posts off topic.

Actually, looking at the thread Title and then seeing what it became from about post three, every post from there strictly speaking was off topic, but it was and is a really interesting thread and I thank devo for bringing up here.

I hope bob c responds to my reply.

What if the actual weight of the top floors was heavier than the estimate. Would that have caused a faster drop rate?

Hi bob c,

It is my opinion only, but as I mentioned is a previous post, I think the WTC Towers appeared to fall quicker than may have been the case if counted from the top most floor. The top ~20 floors fell in one block until it came and landed on the rest of the buildings debris below. Does that make sense to you? My brain is kinda hurting at the mo'!................. With the Towers being 110 storeys, deduct ~ ⅕ off the free fall time, which equates to the ~20 floors the Towers fell from. If I have this wrong I would be obliged if it could be explained to me?

What if the actual weight of the top floors was heavier than the estimate. Would that have caused a faster drop rate?

Take care.

Do you think the weight of the top 20 stories dropping onto the floors below would have any inertia? No of course not. It was Mr Atta and his friends who quickly planted explosives before the fuel ignited.