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indazona,

 

I'm certain with your knowledge you know it's a simple (1/2)*Mass*Velocity-Sqaured calculation, but yeah, we'll let RMT present that analysis

Exactly and that's why I'd like Ray's input.

As you know, the basic algebraic equation for kinetic energy assumes an idealized situation where the object giving up the kinetic energy and the object receiving the kinetic energy are billiard balls (point particles).

 

Of course, in the real world aircraft and sky scrapers aren't point particles, they aren't rigid structures and upon impact they do fold, spindle, mutilate, accordion, twist, shear, deform and generally fly apart into millions of individual pieces. They don't transfer their inertia the same way that idealized point particles transfer inertia.

 

 

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Darby & Zona,

 

indazona,

 

Excellent job with your response. Outstanding.

I agree. And I'm trusting him to design the buildings at my Colorado property, so he'd better know his stuff! :)

 

I'll leave this one up to RMT because he has the data...

 

What was the approximate kinetic energy transferred from the aircraft to the buildings on impact?

Yes, I am remiss in providing this analysis, as I had promised it earlier in this thread. Essentially, one of the most instructive analyses we could perform on this issue relates to comparing how much kinetic energy was considered for an airplane impact for the WTC building design to the amount of kinetic energy that the buildings were actually exposed to on 9-11. The difference is quite astounding, and what is even more astounding is the fact that the buildings continued to stand after both of these impacts! :eek: But before I present the numbers of this comparison it is important that we review some quotes. Let's begin with the quotes made by Leslie Robertson after 9-11. He was one of the people involved in the WTC structural design. I have highlighted the important points of what he said:

 

One of my jobs was to look at all of the possible events that might take place in a highrise building. And of course, in New York there had been two instances of aircraft impacts, the most famous being on the Empire State Building. Now, we were looking at an aircraft that was not unlike the Mitchell that ran into the Empire State Building. We were looking at an aircraft that was lost in the fog, trying to land. It was a low-flying, slow-flying 707, which was the largest aircraft of its time. And so we made calculations not anywhere near the level of sophistication that we could today. But inside of our ability, we made calculations of what happens when an aircraft goes in and it takes out a huge section of the outside wall of the building. And we concluded that it would stand. It would suffer but it would stand. And the outside wall would have a big hole in it, and the building would be in place. What we didn't look at is, what happens to all that fuel? And perhaps we could be faulted for that, for not doing so. But that, for whatever reason, we didn't look at that question of what would happen to the fuel.

 

–Leslie Robertson, interviewed in New York: A Documentary Film, by Ric Burns

Two things here are important. First is his admission that they did not look at the fuel burning. All they looked at was the initial impact. Since the buildings did not fall immediately, but only after the fires had burned for an hour or more, then it is instructive to note that the initial analysis did NOT consider anything beyond the airplane impact.

The second thing he says is very important... that they considered a scenario of an airplane that was "low-flying, slow-flying." This is very important because as Indazona has pointed out, kinetic energy scales with the SQUARE of the velocity! Furthermore, there is a very good reason why they would NOT bother analyzing an aircraft flying into the buildings at 500 mph or more... that reason has to due with air traffic LAWS that restrict how fast an airplane is permitted to fly when below an altitude of 10,000 feet. It is against the law for an airplane to fly in US airspace at a speed greater than 250 knots (about 288 mph) while below 10,000 feet. This is an FAA operating restriction, and it is also an operating restriction that all other countries on earth adhere to. Why is this important? Because if the design scenario that they were considering for the WTC design was related to "an aircraft that was lost in the fog, trying to land" (no one has EVER said they were considering a terrorist action in the design!), then it stands to reason that since the WTC towers are well below 10,000 feet that the fastest an airplane would ever be traveling when it hit the towers would be 250 knots (288 mph, or about 422 feet per second). Now, before we do the comparative energy analysis, let's look at some other things that Robertson had to say:

 

From: Robertson, Leslie E. (2002). Reflections on the World Trade Center. The Bridge Volume 32, Number 1. National Academy of Engineering. Retrieved on 2006-07-28.

 

According to Robertson, the modeled aircraft weighed 263,000 lb (119 metric tons) with a flight speed of 180 mph (290 km/h), as in approach and landing, which would have been much slower than the actual impacts of 9/11.

So Robertson even tells us that the speed they considered was quite a bit slower than the 250 knot (288 mph) speed limit by the FAA. Clearly, this speed they used is definitely along the lines of an approach and landing speed for an aircraft (and yes, I think I ought to know!). So now let us run some numbers for comparison. We do know that the mass (weight) of a 707 was fairly close to the weight of the 767's that hit the WTC, so there is really no point in using various weights, especially since it is VELOCITY which has such a large impact (pardon the pun) on the kinetic energy that the buildings would have to absorb. So let's use the same weight (263,000 pounds, or about 8174 slugs of mass) for all three of the following calculations:

1) First let us calculate the ideal kinetic energy of an airplane impacting the WTC at the speeds that Robertson said they considered in the design (180 mph, which is about 264 feet/sec):

 

Kinetic Energy = (1/2)*Mass*Velocity^2

 

Kinetic Energy = (1/2)*(8174 slugs)*(264 feet/sec)^2

 

Kinetic Energy = 284,847,552 pound-feet = 386.2 MegaJoules

 

2) Now let us calculate the ideal kinetic energy of an airplane impacting the WTC at the maximum speed allowed by Air Traffic Control when below 10,000 feet altitude (250 knots, which is about 422 feet/sec):

 

Kinetic Energy = (1/2)*(8174 slugs)*(422 feet/sec)^2

 

Kinetic Energy = 727,829,308 pound-feet = 986.8 MegaJoules (wow, quite a bit higher, huh?)

 

3) Finally, let us calculate the ideal kinetic energy of the fastest airplane that hit either of the two WTC towers on 9-11, which was approximately 520 mph (about 763 feet/sec):

 

Kinetic Energy = (1/2)*(8174 slugs)*(763 feet/sec)^2

 

Kinetic Energy = 2,379,324,703 pound-feet = 3226 MegaJoules!!!

 

So they hit the buildings with OVER 800% MORE ENERGY than Robertson claims they considered during the design! That is an awful lot of energy, and what is more amazing is that the towers ACTUALLY DID withstand that initial impact without toppling over!

 

Now, there have been some claims that the design of the WTC towers considered the 707's flying at their top cruise speed, which was about 600 mph. It is one thing to SAY that some analysis was done that "proved" the buildings would not fall at 600 mph, but it is another thing to actually produce that analysis so it can be reviewed for its technical accuracy. Let's see what NIST said about such a claim:

 

http://fire.nist.gov/bfrlpubs/fire05/PDF/f05119.pdf

 

A three-page document from the Port Authority of New York and New Jersey (PANYNJ or Port Authority) Indicates that the impact of a Boeing 707 flying at 600 mph was analyzed during the design stage of the WTC towers in February/March 1964 (Letter with an attachment dated November 13, 2003 from John R. Dragonette(Retired Project Administrator, Physical Facilities Division, World Trade Department) to Saroj Bhol (Design and Engineering Department, PANYNJ).

 

No documents on the aircraft impact analysis are available to review the criteria and method used in the impact analysis of a Boeing 707 aircraft on the WTC tower and to verify the assertion in the three-page document that "...such collision would result in only local damage which could not cause collapse or substantial damage to the building and would not endanger the lives and safety of occupants not in the immediate area of impact." Without the original calculations of the aircraft impact analysis, any comment on the document would be a speculation.

Again, I have emboldened the parts that are most crucial. No one can produce a document that has this analysis. So to simply trust this 3 page document from PANYNJ that talks about the analysis, but not be able to see and validate the analysis itself, it truly WOULD be speculative, just as NIST has said. Moreover, we also do not know if this 600 mph analysis considered anything more than the impact only (such as the weakening of steel columns by unextinguished fires). And furthermore, we already have Robertson himself stating that they DID NOT consider the impact of fires after an aircraft impact.

But even if we do accept the 600 mph analysis, we have already seen (from 9-11) that the towers DID withstand the initial impact of the airplanes. The towers DID NOT come down right away, and the fact that they came down only after a period of time where fires were raging on the damaged floors does lend technical support to the NIST conclusions that the towers fell as a result of the initial damage, the transferring of total loads to the remaining columns, and the weakening of the steel due to the heat of the fires.

 

Now, the thing I have not addressed here (as yet) is what Darby related to in his last post: How all this "ideal kinetic energy" was dissipated at and after the impact. Obviously, the large part of the energy dissipation was as mechanical forces which were responsible for severing the columns and wreaking havoc inside the building as the remains of the airplane cut through it. But in such collisions like this, there is also quite a good deal of energy dissipated as HEAT due to friction. The heat of metal-on-metal friction at speeds in the range of 520 miles per hour is very significant! Significant enough that a large number of sparks would have been generated to ignite jet fuel, but also to create enough heat that would actually begin to melt the aluminum from the aircraft!!!

 

I think that's enough for now...

 

RMT

 

 

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ruthless,

 

something about it just doesent make sense.

If you can quantify what it is that doesn't make sense in your mind, I might be able to help. Is it possible that what doesn't make sense may be related to some form of physics you think "should be" one way, when in fact the truth of the physics says something different? This happens a lot, and it is nothing to be ashamed of.

 

i would like to see one experiment. a scale version of the incident, that would tell alot.

I can guarantee that NO SCALE VERSION would EVER satisfy the "true believer" Conspiracy Theorists, for they would use their same ignorance of physics to make claims that the scaled demonstration was somehow "incorrect". There is a concept called DYNAMIC SIMILARITY which dictates when a scaled model faithfully matches the full-scale version. The principles of DYNAMIC SIMILARITY result in scaled test requirements that might not be "obvious" to a person uneducated in the science and engineering disciplines, but they are quite valid.

A perfect example will allow me to explain a parameter I introduced to you in another thread, but did not endeavor to explain: Reynold's Number. This number (named after Osborne Reynolds, a pioneer of fluid dynamics) is actually a dynamic similarity scaling parameter used in aerodynamic wind tunnel testing of scaled models of full-sized aircraft. In short: If a scale model is flying at the SAME Reynold's Number that would be experienced by the full size vehicle, then ALL of the forces on the vehicle (inertial, viscous, and pressure) are dynamically similar. The definition of Reynolds Number is:

 

Re = (Fluid Density)*(Characteristic Length)*(Fluid Velocity)/(Fluid Viscosity)

 

"Characteristic Length" would be the scaled measurement, which is related to the scale factor. The other parameters should be self-explanatory. But now here is where a person unfamiliar with dynamic similarity might think "all I need to do is scale the velocity with the same scale factor that I scaled the vehicle geometry and it will be an accurate scaled demonstration." This would be terribly incorrect. The reason is that the full size aircraft might be flying much faster, but it is also flying at a higher altitude than you would test in a wind tunnel. As altitude increases in the atmosphere there are significant changes in the density and the viscosity of air. So to run a faithful scale test in a wind tunnel at (approximately) sea level altitude, you will have to adjust the velocity and geometric scale factor to compensate for the changes in density and viscosity. In fact, this often results in engineers testing very high speed aircraft in WATER TUNNELS, because the difference in density between air and water helps compensate for the big changes in velocity between the model and the full size.

 

Now, it is not hard to see how an UNINITIATED person (who did not understand dynamic similarity) would scream and stomp their feet that "it is NOT VALID to test the airplane in water when it actually flies in air!", but in fact this is their ignorance talking, for as long as the concept of Reynolds Numbers being equal is adhered to, it WOULD BE A VALID scale demonstration. Do you see what I am getting at? Some engineers could spend HOURS and HOURS of time developing a TRULY ACCURATE scale demonstration (and I would bet some have already!), but for no other reason than a COnspiracy Theorist does NOT UNDERSTAND PHYSICS, they would claim it was not a valid test because the parameters were not "identical". When in fact, the engineer applied much deeper concepts than would seem obvious to ENSURE it was a faithful representation.

 

This is the exact sort of area where people who are ignorant of science and engineering should avoid making pronouncements based on what THEY BELIEVE is true, for it could be quite incorrect indeed.

 

RMT

 

 

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theres a few things i'd like to say, and i hope some people dont hate me too much for changing my opinion, but rmt, i think your right. after you told me how you believed the wtc's fell, ive been thinking about it and visualizing it. your scenario makes perfect sense.

 

the thing about it is, i dont know your physics very well at all, but my physics i know very well. i spent half my life devising my own system of physics, only to find out that i shouldve learned the real physics, cause without it, i cant tell anyone what im thinking.

 

but i will try to convey what im thinking in plain talk :)

 

at the front of the wtc, the steel beams were sheared. they were not sheared in the backside, wich caused the balance of weight to shift to one side. the steel was strong, so it held it up, until fires softened the steel. it was probably already overloaded before the steel was softened, but not noticable. finally the steel that was left... scratch that, ive got a better idea, a visualization. grab a paperclip, unfold it, and straighten it out. now imagine that straight piecce of metal is a beam in the wtc. grab the top with your thumb and index finger, and roll your wrist. this is what i think happened to the collums left. the collums were twisted with great force, and once it started going, it wasnt about to stop. way too much weight.

 

would this assumption be correct rmt?

 

and about the planes in water, i think that when testing drag, water would be the ideal medium. but, i think when testing lift, water would be the worst medium.

 

say a foolhardy kid, like me, decides to make a plane, and he tests it in an underwater environment. the plane has outstanding lift underwater, but when used in the air, the plane cant even lift itself at max speed. nonetheless the kid is baffled. anyways, just thinking in the open :)

 

i really need to learn physics fully. i cant explain a thing im thinking without it. i am also undertsanding that the things i have observed, i did not realize all of the paramiters that were involved.

 

i remember this cartoon when i was a kid. the kid was playing baseball, did some physics calculation in the dirt, and hit a homerun. everyone in the cartoon was shocked that the geek could hit a homerun, because they couldnt even though they were bigger and stronger. i just laughed at it as a kid, not anymore.

 

blah, blah, blah, i could go on forever. but the point is, i have ALOT to learn.

 

 

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"3226 MegaJoules"

 

are you serious? that is an insane amount of power. i think my capacitor is one joule, and it has enough energy to literally fry me...

 

you know, the more i think about it, the more i think that the fires didnt even matter. i am thinking that if there was not a single fire, the buildings still wouldve fallen.

 

now this one may seem silly, but i have to ask. is it possible for steel to liquify from being bent very rapidly, or from being bent over and over again? could this possibly explain the melted steel?

 

 

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Let me reply to this one first. I'll reply to the other one when I have more time:

 

"3226 MegaJoules"

 

are you serious? that is an insane amount of power.

The equations, and their results, don't lie. The best part is you can check them yourself! ;) But one minor terminology nitpick (which is important to engineers). The measure called "Joules" is a measure of energy, not power. Technically speaking, power is energy (consumed or dissipated) per unit time. So the units of power would be Joules/Sec, or something similar.

 

you know, the more i think about it, the more i think that the fires didnt even matter. i am thinking that if there was not a single fire, the buildings still wouldve fallen.

The problem is the evidence does not support this conclusion. If this were true the towers would have fallen within a few minutes of the impacts. The impact certainly caused a great deal of destruction, and even caused resonant oscillations in the building, but these eventually damped out. Without the heat weakening the columns, it would have required some other "forcing function" (such as a stiff wind) to induce another dynamic event. Without the fires, the buildings would have again assumed a static situation. The dynamic changing (reducing) of the steel rigidity is what caused the deteriorating situation.

 

now this one may seem silly, but i have to ask. is it possible for steel to liquify from being bent very rapidly, or from being bent over and over again? could this possibly explain the melted steel?

Not unless the "steady state" temperature of the steel was very high (close to the melting point) to begin with. Bending does introduce energy in the form of heat to a metal that is being bent. But if the steel is far from its melting point, the heat due to bending is not enough to get it to the melting point. The initial fires were not enough to melt steel, but certainly more than hot enough to melt the aluminum that made up the airplane. If there was any steel melted, it was likely during the fires in the "heap" after collapse, where enclosed fires could get to much hotter temperatures than they could in the free-standing building.

I'd ask Indazona to correct me on any of this, if necessary... since I am a structural neophyte compared to him! ;)

 

RMT

 

 

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"The problem is the evidence does not support this conclusion. If this were true the towers would have fallen within a few minutes of the impacts. The impact certainly caused a great deal of destruction, and even caused resonant oscillations in the building, but these eventually damped out. Without the heat weakening the columns, it would have required some other "forcing function" (such as a stiff wind) to induce another dynamic event. Without the fires, the buildings would have again assumed a static situation. The dynamic changing (reducing) of the steel rigidity is what caused the deteriorating situation"

 

ok, your the expert, but i would ask this: metal heats when it bends, correct? a slow bend in a giant steel beam should create a good bit of heat, correct? like i said, just open thinking. :)

 

 

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Hi again, ruthless:

 

but i would ask this: metal heats when it bends, correct? a slow bend in a giant steel beam should create a good bit of heat, correct? like i said, just open thinking.

Open thinking is fine, especially since you keep your mind open to accurate answers. Yes, metal heats when it bends, you are correct. And heat (measured in calories) is actually another measure of energy (just like joules, or pound-feet, etc.). But the amount of heat (energy) generated by steel bending pales in comparison to the amount of kinetic energy of the impact (as stated above) or the amount of energy inherent to the jet fuel for that matter. Furthermore, the heat of a metal bending is a very transient effect. If there were no other heat source (fire) the ambient temperature around the metal would quickly cause the temporary heat induced by the bending to be absorbed into the larger "reservoir" of the cooler ambient temperature.

Now...speaking of energy in fuel (which was NOT included in the kinetic energy computation I gave above), what follows is a video of a very recent airplane fire and explosion that took place in Japan on a China Airlines 737. Just look at the energy released, and then consider that this airplane is SMALL and had reached its final destination (tanks were not full), as compared to a 767 which is just beginning a transcontinental flight...

 

http://news.orf.at/video/iptvpopup.html?japan_plane_update_edit.wmv

 

This jet fuel burned the entire plane, and the additional combustible material in an airplane pales in comparison to the paper and furniture and other combustible material that was inside the WTC towers!

 

RMT

 

 

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two things,

 

first thing is, i would like to explain my thinking behind this. i have a plastic chair that is broken on the back. in the winter, it supports me. in the summer i slide right through it. and in the fall/spring something strange happens. it will hold me up for a certain period of time, then it will warm up and i will slip through. something just crossed my mind though, maybe its my back that warms the plastic and makes it slip. just a ponder. :)

 

and the second thing is,

 

"Now...speaking of energy in fuel (which was NOT included in the kinetic energy computation I gave above)..."

 

im having a hard time grasping how much energy this actually was, because to me, it seems enormous.

 

this may seem like a stupid question, but it may help me to understand how much energy was released. how much tnt would be needed to produce the same amount of energy? my guess would be a kiloton or more, but im probably way off.

 

 

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ruthless,

 

well, i did some digging, and i think i have an idea of how much energy that was. i was way off lol.

 

"The bomb had a yield of about 21 kilotons of TNT, or 8.78×1013 joules = 88 TJ"

You are showing more and more traits of thinking like an engineer everyday. ;) You have found an energy conversion factor! Go to the following web page, type in "3226" in the top box, then select "MegaJoules" in the left box, and finally select "kiloton [explosive]" in the right box. Hit the "convert" button and you will see the conversion!

http://www.onlineconversion.com/energy.htm

 

Still quote an explosive force (about 0.77 tons of TNT) but nothing like a Fat Man, of course!

 

RMT

 

 

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"The bomb had a yield of about 21 kilotons of TNT, or 8.78×1013 joules = 88 TJ"

 

a reference to the "fat man" bomb dropped in ww2.

 

its jaw dropping to think what the human mind is capable of.

ruthless,

It is especially jaw dropping when you consider that the 21 kt of yield was produced by the conversion of 1 gram (not a kilogram...a single gram) of mass to energy.

 

 

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ruthless,

 

theres a few things i'd like to say, and i hope some people dont hate me too much for changing my opinion, but rmt, i think your right. after you told me how you believed the wtc's fell, ive been thinking about it and visualizing it. your scenario makes perfect sense.

That's nice, but even more important than "making sense" is the fact that all of this can be modeled and verified as true with existing physics. IOW, it can be shown to be a true and accurate representation of how the building came down. I could give you the equation for momentum (Mass*Velocity) and we could create a simulation program that shows that, even while the velocity of the falling top portion of the towers would eventually reach a constant (terminal) value, the mass of the falling object itself would continue to grow as each new floor collapsed. This is the VERY LARGE value of engineering that is so often "behind the scenes" that citizens of our country never see, never understand, and never come to appreciate how it has made such large differences in our lives.

 

the thing about it is, i dont know your physics very well at all, but my physics i know very well. i spent half my life devising my own system of physics, only to find out that i shouldve learned the real physics, cause without it, i cant tell anyone what im thinking.

And without wishing to sound insulting, the problem here could be "What if your physics is incorrect with respect to physics that has already been vetted as representing reality?" This is precisely what I am talking about when I speak of people who "think a certain event should happen a certain way" and use the excuse that "logically, it should be this way". Often times the reality of physical mechanics can go against what you think is logically true. Take for example aerodynamic forces (drag and lift) that I have been explaining to you. Most people who do not understand aerodynamics would say it is "logical" that if the airplane travels twice as fast that it should generate twice as much lift and drag. Sounds logical, right? But such a notion is WRONG because the physics of dynamic pressure (the quantity the lift and drag scale with) tells us that we would actually be producing FOUR TIMES as much lift and drag if we doubled the airspeed velocity. This is because dynamic pressure scales with the SQUARE of velocity. This is just one example, and there are plenty of other examples in solid mechanics (structures) that I am sure Indazona could highlight to us.

 

at the front of the wtc, the steel beams were sheared. they were not sheared in the backside, wich caused the balance of weight to shift to one side. the steel was strong, so it held it up, until fires softened the steel. it was probably already overloaded before the steel was softened, but not noticable. finally the steel that was left... scratch that, ive got a better idea, a visualization. grab a paperclip, unfold it, and straighten it out. now imagine that straight piecce of metal is a beam in the wtc. grab the top with your thumb and index finger, and roll your wrist. this is what i think happened to the collums left. the collums were twisted with great force, and once it started going, it wasnt about to stop. way too much weight.

 

would this assumption be correct rmt?

In general this is one valid way of thinking about it. It was CERTAINLY over-loaded before the fire softened the steel, but that is because designers design-in what is called "margin" or "factor of safety" so that it could keep standing even when a fair number of columns were severed. But I have highlighted in bold the words of yours that are most especially correct and pertinent. These words accurately describe the differential equation that governs column buckling forces with respect to lateral (sideways) deflection. A column holds its load the best when it is straight up and down (in-line with the gravity vector). As the column begins to deflect laterally (sideways), the more it deflects the greater the force becomes that tries to buckle the column. It is only the inherent rigidity of the column (Young's Modulus) that can counter this buckling tendency. SO now once the fire weakens the rigidity of the steel, it will reach a point where it CANNOT counter the lateral deflections... once the lateral deflection gets beyond a critical value, it keeps going until the ultimate failure of the column.
and about the planes in water, i think that when testing drag, water would be the ideal medium. but, i think when testing lift, water would be the worst medium.

Again, I can understand how you would "logically" think this way. But the reality of the physics clearly state the aerodynamic forces of drag AND lift are both directly dependent upon the density and viscosity of the fluid the body is moving through. Above and in the other thread I mentioned DYNAMIC PRESSURE, and you might not even know it but I gave you the equation for it. We use a symbol of a "q" with a bar over it ("q-bar") to represent dynamic pressure. And the equation goes like this:

q-bar = (1/2)*(Fluid Density)*(Fluid Velocity)^2

 

So simply by changing fluid from air to water, I can STILL produce the same dynamic pressures (which result in the same lift drag forces the airplane would see in air) but I can create those forces at MUCH lower fluid velocities in water, because water is so much more dense than air.

 

i really need to learn physics fully. i cant explain a thing im thinking without it. i am also undertsanding that the things i have observed, i did not realize all of the paramiters that were involved.

This is one of the joys I get out of teaching (God knows the pay ain't all that great!)... seeing the "light go on" above students' heads when they "get it". The stuff about aerodynamics that I have started to help you understand are REALLY basic and fundamental. But to a freshman engineering student they can seem quite difficult. I always enjoy telling my freshman classes that "if you think this is hard, just wait until the kinds of complex problems you will be able to solve if you make it to your junior and senior years! This stuff will be a CAKE WALK compared to that!" And without failure, I will always have a few students come back to my office when they finish junior or senior year and tell me "you were right...that early stuff was REALLY easy, and I understand it really well now. But it is amazing how I can now solve problems that are much more complex."

 

blah, blah, blah, i could go on forever. but the point is, i have ALOT to learn.

And the learning NEVER ends. The day an engineer stops being an effective engineer is the same day that engineer stops asking questions or trying to model reality so as to produce a better design. Once again, ruthless, I would encourage you to energize your life by looking into going back to school and studying science and engineering. You will not only learn a lot, you can create a very nice career for yourself, and you can contribute things to society that would benefit all mankind.

Do it... you have my support!

 

RMT

 

 

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"And without wishing to sound insulting, the problem here could be "What if your physics is incorrect with respect to physics that has already been vetted as representing reality?"

 

yeah, alot of my physics is incorrect. sometimes thats a tough pill to swallow, but i also realize that i never got to do any serious experiments, and i also realize that if i were to, i would not have fully understood everything. more importantly, i would not be able to convey anything i did learn. i have to be honest, i dropped out of school in the 6th grade. when i dropped out, i was learning about geometry, i never got any further than that. years later, i went and got my g.e.d. i just went up there and took the test. luckily i passed. :) i know that i need to go back to school, and i will very soon. i have been looking at online colleges, and im thinking about msu. when i was young, i wanted more than anything to have a normal "routine." and for about 7 years now, ive had a pretty normal routine. what i didnt realize when i was a kid was, its harder than a mofo to break a routine once you get used to it! anxiety sucks, and i hate making excuses.

 

imagine having to jump into a lake of hungry crocodiles, i akin the way i feel to that. lol

 

i am going to force myself to go. you and darby have more than inspired me to go. i look up to both of yall, and i hope that one day i can communicate on your level. as a matter of fact, i think im going to go talk to a few people, and make some phone calls and see what i can come up with.

 

and thank you for the words of encouragement, it means alot.

 

 

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Are we still on the 9/11 Theory? If so, can I dump some questions here so I screw up people's thoughts and arguments?

 

If fire can make it so the TT's colapsed, why have skyscrapers gone through fires (older buildings no less) and survived? Don't say because they old - the technology was less efficient.

 

If the weight of the plane, even, the fire and the weight of the plane plus damage, caused the TT's to fall, why have other skyscrapers, who also have had planes gone into them... survived?

 

How many support structures are there? And could an aluminium (unneccessary and obvious detail) plane really break a through a steel one?

 

Why didn't the fire suppression systems kick in?

 

Why did it require an explosion for the building to colapse, if weight was the problem?

 

Why was it marked pancake when the colapsing floors had an incredibly fast decent (and had even sprayed - and damaged, other nearby buildings)?

 

Why did the TT's (who had never done this before, ever) practiced massive evacuation drills only weeks before the event? Who where those people who entered the building after the massive evacuation drills?

 

Why would it take a large group of people to plant explosives? Why not a very fast crack force, or an automated system? Why not a single person over a long period of time?

 

If it was destroyed by explosives, how could we be sure it was the government?

 

Why was the CIA aware of the planes, but did nothing?

 

Why did the local airspace radar not raise an alarm?

 

Why didn't the airport radar raise an alarm?

 

Who were the first people on the scene? Why were they so fast?

 

Why aren't there any damn parachutes on the roof?

 

Why were no helicopters scrambled to rescue people from the roof?

 

Why hasn't an investigation been held into the debris to see exactly how it colapsed?

 

Why has information on 9/11 been withheld?

 

Why does an army demolition expert believe explosives were used?

 

What would the government have to gain if they were to do this? If not the government, why would the terrorists, or even, anyone, want to destroy the TT's? Why do it on a day when the fewest amount of people would be there?

 

How comes, if there was a fight onboard one of the planes, that the planes both hit their targets relatively level?

 

Have fun.

 

 

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ruthless,

 

and for about 7 years now, ive had a pretty normal routine. what i didnt realize when i was a kid was, its harder than a mofo to break a routine once you get used to it! anxiety sucks, and i hate making excuses.

Not only do you have my support, you have my respect. I may have related this story to you before (or not) but there is a young guy who works for me (~27 years old) who is actually DOING reliability engineering, yet he has no degree. He will never get promoted, his raises will be substandard, and he can never go to another company without that degree. He is stuck, but he has "natural talent". However, he is not only stuck in his routine, but each time I push him to go back to school all he can do is make excuses. And let me tell you, I push and goad him and explain to him his "long term outlook without a degree" on a weekly basis. I try to get him to look past 30, look past 40, and into his 50s and consider just how much he will NOT be making and that his life will NEVER be more comfortable than it is now. He will always be on the edge, paycheck to paycheck, and will never be able to afford a house (here in California).

You, however, have something he does not have: The knowledge that ONLY YOU can hold yourself back, and you do it by making excuses for why you "can't". My father constantly told me "All the 'I can'ts' lay in the cemetary six feet under!" YOU HAVE THE RIGHT OUTLOOK AND YOU HAVE GOTTEN BEYOND THE BIGGEST MENTAL BLOCKADE!

 

I will guarantee you one thing for certain: Once you have that degree and are working in your chosen field I GUARANTEE you that you will ALWAYS look back and say "I am glad I did that" and you will NEVER look back and say "I regret doing that". And I would even surmise that your family will say the same thing! :)

 

Whenever you need any advice or support, you let me know, my friend.

 

RMT

 

 

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As I understand it, the girders were constructed around a central core, so that a large open, commmercially valuable, space would be created between the central core and the steel exterior.Tying the central core and the outside skin together were steel trusses which were bolted with a pair of 1/2" bolts on one end and a pair of 5/8" bolts on the other end.

 

As a result of careless handling, chunks of the foam (we have a technology that seems to be vulnerable to foam)were knocked off, exposing the steel of the truss frame. Not insulated, the steel of the truss frame expanded in the hot air created by the burning interior with the result that they sagged. I suspect that what happened, then, was that the bolt threads stripped and the concrete slab flooring supported by the trusses collapsed. From there on it was pancake city.

 

Sometime later I saw a video of the sought after Osama b.L. who said the collapse exceeded even his own expectations(he was trained as an engineer). He thought maybe a couple of floors would go and that would be about it.

 

 

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Rusty,

 

I am not going to try to answer all of your questions, as I think I realize they are pretty much a "grab bag". But some of them can be answered with very accurate, technical answers. I am assuming you would like to learn and understand the answers, and not throwing them out thinking you know the answers or that they are already satisfactorially answered by certain folks who pitch conspiracy theories. So here are some answers. If you don't agree, would like to discuss them, or would like more details, by all means let me know:

 

If fire can make it so the TT's colapsed, why have skyscrapers gone through fires (older buildings no less) and survived? Don't say because they old - the technology was less efficient.

Efficiency and performance are two different things. The first answer is that you are forgetting that other buildings that experienced fires were not flown into by airplanes traveling at 500 mph, thereby destroying much of their load-bearing structure. A fire may weaken steel in a conventional building fire, but how many of them have lost a LOT of their load-bearing members as well?

Also, the "older technology" for building is much more fundamental and much more rigid than the WTC towers. You COULD NOT use that same highly rigid (and older) building technology in buildings as tall as the WTC towers. That was why the WTC towers were new technology...because it was needed to make the towers that tall AND retain a lot of useable space. Conventional technology uses "box truss" design where the entire building has a regular "skeleton" inside. That means a LOT of redundant load-bearing paths. The WTC towers are best described as a single "core" with a structural "tube" formed by the outside skin. Think of a toilet paper tube. The other walls of the tube provide its rigidity. Break a lot of the columns on the outside of one (or more) sides of the WTC tower "tube", and THEN add fire to weaken the steel columns that remain to hold the load, and you have a MUCH different situation than conventional technology buildings. They really are apples and oranges.

 

If the weight of the plane, even, the fire and the weight of the plane plus damage, caused the TT's to fall, why have other skyscrapers, who also have had planes gone into them... survived?

Please give me the examples and let us deal with them on a case by case basis. I had no idea we had such a plethora of airplanes hitting tall buildings in our history! ;) The only other one I know of was about 1 year after 9-11 when a light (general aviation) airplane ran into a tall building in Florida. Just comparing the mass, momentum, and energy of that plane with the large jets of 9-11 should answer the question of why that building did not fall.

 

How many support structures are there? And could an aluminium (unneccessary and obvious detail) plane really break a through a steel one?

I think it should be obvious because we actually SAW real (aluminum) airplanes penetrate the steel columns of the outer tube of the WTC towers. Perhaps you could make your question more specific so I could understand what you are really getting at?

 

Why didn't the fire suppression systems kick in?

Some did, but on lower floors from where the airplane penetrated, where they did no good. The sprinkler systems utilized central "standpipes" that were located in the core of the towers. The cores of both towers were significantly damaged by the airplanes as they penetrated, thus severing the standpipe lines that would be used to carry high pressure water to the damaged floors.

 

Why did it require an explosion for the building to colapse, if weight was the problem?

This is a crucial question that the conspiracy theorists MUST answer, because expert analysis says it was not required. This is what myself and Indazona have pointed out about Euler column buckling: If engineering analysis can show that the lost columns + fire heat was enough to induce buckling (and there was clear evidence that buckling was occurring) how can you make a case that it HAD TO BE brought down by explosives?

 

Why did the local airspace radar not raise an alarm?

 

Why didn't the airport radar raise an alarm?

Do you understand how air traffic control radars work? It would seem from these questions that you do not. Are you aware that the airplane transponders (which the terrorists turned off) are a primary component for identifying which airplane is which? What, specific, type of "alarm" do you think these radars have, or should have?

 

Why aren't there any damn parachutes on the roof?

How many "average folk" are trained in how to use a parachute much less skydive safely off a building? It is not as easy as you might think (and I have been trained to skydive and done it 3 times in my life). You could pose the same question about why are there not parachutes on commercial airplanes for every passenger? How often does an airplane have a problem in cruise flight where there is enough time for everyone to don parachutes and jump?

 

Why does an army demolition expert believe explosives were used?

Belief is not sufficient to show that explosives were actually used. He would not only have to provide evidence, but as mentioned above he would have to lay out why explosives were REQUIRED (i.e. Euler column buckling could not have possibly been the failure mode that brought them down).

 

How comes, if there was a fight onboard one of the planes, that the planes both hit their targets relatively level?

I could be wrong, but I get the feeling you are mixing up the WTC airplanes with the Flight 93 airplane that crashed in Pennsylvania. That was the airplane where we know the passengers struggled with the hijackers. I have seen nor heard no evidence that either of the two WTC-bound airplanes experienced a struggle between passengers and the hijackers. Certainly the first airplane to hit the WTCs, the passengers could have no idea what the hijackers were planning to do. And given how quickly the second airplane hit as well, it is unlikely the passengers on that airplane would have heard news that the first plane hitting was a purposeful terrorist act in enough time to react to their situation.

Some are good questions, some I think you simply need more knowledge about physics or the buildings themselves. Some are questions (mostly the ones I did not address) that cannot be answered by physics or engineering, as they are questions about why people acted, did not act, or knew what they knew.

 

RMT

 

 

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And so once again the topic turns to 911...

 

the bolt threads stripped and the concrete slab flooring supported by the trusses collapsed. From there on it was pancake city.

I have read this too from the 911 commision. Follow my logic because if thier is a flaw in it I would like it pointed out.

First off it is my understanding that a fire can only burn as hot as its fuel which would be the jet gasoline. Now then the majority of this "jet gas" burned up on impact igniting everything flamable but ultimiatly expending the strongest fuel(the gas).

 

So the towers burn awhile. NOW THEN, for some reason the tower that was hit second fell first...but let us overlook that for now and continue. When it fell the feds would have the world believe that it was due to the trusses heating up , expanding and "popping" the collums out of place displaceing the weight and causeing collapse... Thing is we gotta go back to the tempature of the fire which was an open air fire so it wasn't burning that hot. Certianly if the fire could heat the trusses to the point where they expand then what we have to accept is that the trusses were heated to plasicity. PROBLEM even if the fire burned for hours it could never reach tempatures hot enough to expand the trusses due to the lack of oxygen(amongest many other factors), the fire was indeed being smoothered by itself as was the WTC design plan just incase the fire suppresion system failed...That WTC has one marvalous building... Let us assume that the fire had burned hot enough and long enough (two key critical points any 911 analyst must understand) to expand the trusses. The collums are much larger (which means they take longer to heat up) and sturdier than the trusses.

 

If the trusses expanded they would bend, break, and fall but they would not pop or bend the collums out of place. Trusses are weilded together and since they had already reached plasicity thier weilds would give before a gaint solid cast steel collum(you are aware that the inner collums are the size of moblie homes right? Thier HUGE) SO THEN even if all the trusses on one or two floors failed you still have 30 stories above of intact trusses and 70 stories below of solid trusses that would continue to hold the inner and outer core together. The floors were supported by beams which interscted the inner core so it is unlikely the loss of a few trusses would cause a critical failure. So the floors aren't gonna fall down over the support beams onto the floors below them.

 

You can also see pictures of pancaked buildings on an image search. In all the images I have seen the buildings relatively remained intact unlike with the WTC which turned into powder...Funny the lack of large concrete chunks considering how much concrete was in the core..why you'd figure in a pancake collapse that the breaking beams would of flung LARGE concrete chunks into New Jersy..but instead the concrete powderized...hmmmm Funny that.

 

And So no matter which why you want to argue it the North Tower fell... Then about some 20 odd minutes later the south tower which had been hit first , and had taken a direct impact into its inner core section, AND burned for about 45 minutes longer then its twin finnaly fell into its footprint...many hours later the 47 story Solomon building which suffered no plane impact would also fall into its footprint.

 

Of course Fire Fighters trained in structrual demolition and Silverstien the Fire Chief is another subject to contemplate altogether.

 

 

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Hello rusty,

 

Who the heck are you? You kinda weird me out man. But I admire your stance for truth...so I guess you can't be that creepy...Then again god only knows right? Whats really stranger than strange though is you commenting on this thread with my position...I almost wanna ask if your a TT but I know you already stated no..so..ok then.

 

I hope you don't mind if I address RAIN MAN TIME. I think he could still use some more imput into his perspective.

 

 

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Rusty,

 

I am not going to try to answer all of your questions, as I think I realize they are pretty much a "grab bag".

Avoidence

 

that they are already satisfactorially answered by certain folks who pitch conspiracy theories.

riddicule

 

A fire may weaken steel in a conventional building fire, but how many of them have lost a LOT of their load-bearing members as well?

unsubstantiated or invented information. You can not know how many IF ANY "load-bearing members" (HUGE STEEL COLUMNS!) failed because the "load-bearing members" were never examined but instead shipped off to china for for recycling. And you certianly weren't inside the WTC to examin the Cloumns first hand.

 

Also, the "older technology" for building is much more fundamental and much more rigid than the WTC towers. You COULD NOT use that same highly rigid (and older) building technology in buildings as tall as the WTC towers. That was why the WTC towers were new technology

Which is why they are also refered to as "Supertalls" They set a new standard for the word skyscraper...also the WTC was a new architectural design. Technology and Architecture are two words with different meanings.

 

Break a lot of the columns on the outside of one (or more) sides of the WTC tower "tube", and THEN add fire to weaken the steel columns that remain to hold the load, and you have a MUCH different situation than conventional technology buildings.

Glad to see you know a little about it..However you should remember that the outter tube was also a steel mesh. Kinda like a screen on a porch door. You can poke a hole..heck you could stick your fist through a screen BUT the screen will not unravel.. You will have a hole yes but the rest of the screen will hold itself together. As for the problem with expanding trusses..I already explained that to in my reply to Packer.

 

Please give me the examples and let us deal with them on a case by case basis. I had no idea we had such a plethora of airplanes hitting tall buildings in our history! The only other one I know of was about 1 year after 9-11 when a light (general aviation) airplane ran into a tall building in Florida. Just comparing the mass, momentum, and energy of that plane with the large jets of 9-11 should answer the question of why that building did not fall.

The copy cat teenager that sacrificed his life to destroy some office space. I'm supprised you remember that. Yup, that was one dumb kid...Of course thier is the Empire State building but that was a differnt architectual design and a differnt kind of plane...apples and oranges No?

 

I think it should be obvious because we actually SAW real (aluminum) airplanes penetrate the steel columns of the outer tube of the WTC towers.

It should be equally obvious that the steel columns of the outerskin pale in comparision to the interior support columns.

 

The cores of both towers were significantly damaged by the airplanes as they penetrated, thus severing the standpipe lines that would be used to carry high pressure water to the damaged floors.

NOW THIS SENTENCE!!!..*chuckle*... To know how the cores were affected is to know where the planes impacted. The South tower was a direct dead on hit. The North tower however, was a corner clip..the plane impacted through the corner and the kinetic velocity and fireball missed the core of that building. So the standpipes should of been in complete working order in that building at least.

 

This is a crucial question that the conspiracy theorists MUST answer, because expert analysis says it was not required.

I am not a theorist. I do not have a complete hypothesis about 911. Thier is no scientific formula to apply here. All I have are my observations. One observation is the inner core. In a pancake collapse the concrete should of broken up into huge chunks not powderized...The giagantic interier columns should of remained intact, even in a pancake colapse I fail to see how you can envision the columns falling ontop of itself ...they have nowhere to fall they should of remained intact and swayed over landing on other buildings in complete monolithic sections to be cut up later to fit on semi trucks during clean up...The inner core was the anchor of the building which the beams intersected, even if the floor and the outer tube fell away from the core that doesn't expalain how a core fell into/ontop of itself. In the pancake collapse theory the core should ob been standing tall with loads of beams sticking out of it. Trusses did not support the vertical mountian of concrete and steel but since it did fall where were the giant boulder sized concrete chunks of core? ?? Shoot, show me some fist sized chunks of concrete. Am I to belive that the majority of concrete turns in to powder when it falls on top of itself? Even at terminal velocity concrete doesn't powder in the manner displayed by the WTC (it breaks) HOWEVER expolsives will damn sure bring the pressure needed to pulverize concrete....What kind of explosives? I don't know, refer back to the first two sentences of this paragraph. I can point out the inconsistencies but I can't insert truth when I am not certian what the truth is...I am only certian about the lies of 911.

 

Do you understand how air traffic control radars work? It would seem from these questions that you do not. Are you aware that the airplane transponders (which the terrorists turned off) are a primary component for identifying which airplane is which? What, specific, type of "alarm" do you think these radars have, or should have?

Now why is it when Rusty, brings up the whole radar thing you acknowledge him but ignore me when I bring it up? The American flight traffic control system has a failsafe system making it impossible for american airbusses to dissappear in american airspace. When the transponder is turned off the flight traffic controller that was assigned the plane no longer has the flight identification info on his screen. Instead he has the blip and at this point so does every other air traffic controler responsible for that airspace. The plane shows up on everyones screen now so that the other air traffic controlers can steer thier planes around the blip. Meanwhile the guy who lost his plane for a blip should be going apeshit on the inside while calmly explaining the situation to norad after radio contact proved negative. It is all SOP and the A.T.C.S. is well trained and more than capable in a crisis situation....Yet not only was SOP disreguarded on 911 but on 911 after the hijakers turned off thier transponders they enabled the planes stealth mode to avoid being seen as a blip. Officaly the planes lost ALL RADAR CONTACT for a period of time. Only by useing the commercial air busses stealth ablity could the hijakers avoid A.T.C. who would of been monitering and reporting the flight paths of the radar blips....oh wait a minute...commercial air busses don't have stealth technology. So how in the flying Duck did the dissappeare from radar?!?!

I don't have every answer. I do not know the complete truth..I am dead certain about the lies though. It isn't wise to ignore inconsistencies.

 

ME

 

 

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I was wondering when you were going to make some sort of claim in my area of expertise, Mr. Titorite. I noticed you were not able to refute any of the facts I put forth about how wrong your sources were in their structural analysis of steel and the weakening of its Young's Modulus. But as a result of your latest post, I am afraid I have to inform you that you have absolutely no clue what you are talking about in the realm of structural engineering. Period. I could actually show you wrong on several of the things you say, but why bother when I can make you look truly foolish by addressing one, choice analogy you put forward.

 

Glad to see you know a little about it.

Clearly RMT knows way more about structural engineering than you do. But I am more the expert in this area than he, which is why we decided that it was more appropriate for me to respond to your nonsense:

 

However you should remember that the outter tube was also a steel mesh. Kinda like a screen on a porch door. You can poke a hole..heck you could stick your fist through a screen BUT the screen will not unravel.. You will have a hole yes but the rest of the screen will hold itself together.

This is positively the most ridiculous (and highly incorrect) analogy that was ever floated about the WTC external structural skeleton. And I notice you do not even reference the silly fools who first floated it. Are you aware that it only took about 2 microseconds when someone first put forth this dreadfully wrong analogy for someone to point out what is obviously wrong with it? I shall now destroy any credibility you may have had in making claims about structural engineering concepts:

The external structural skeleton of the WTC towers was nothing like a "screen on a porch door" for one fundamentally simple reason: A screen on a porch is not a load bearing structure!It is NOT under compressive stress like the WTC exoskeleton was. This is precisely why a screen on a porch door does not deform, you nincompoop, because there are no compressive loads to do so! To draw this analogy shows how little you not only understand the concepts of structural stress and strain, but it also shows you are willing to parrot someone else's ignorant analogies, thinking they are valid. I know for a fact that RMT got a good laugh out of this silly analogy of yours, which isn't even yours, and I can also bet Mr. Darby was also smiling waiting for either RMT or myself to point out how poor of an analogy it is.

 

So as I see it, you can now either admit how foolish (and incorrect) that analogy is, and at the same time admit you know nothing about structural analysis to be able to make the kinds of claims you have, or you can ignore that you have once again been proven foolish, and try to change the subject yet again. The choice is yours. But if you don't cop your ignorance and admit you were wrong, I assure you that you left several other gems in this last post of yours that will make you look even more silly if I choose to address them.

 

 

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