He had a PhD in Biochemistry. By psikey standards, that makes him qualified to comment on skyscraper physics.
So there. 
Bottom of Gitchi Gummi, bro. The searchers all say they’d have made Whitefish Bay if she weren’t such a fucking sieve. Knew a guy who would’ve been on that trip if he hadn’t spent the night in the Gary tank for getting in a drunken brawl. God watches out for drunks and small children. :rolleyes:
But then he wrote more books on astronomy than anything else.
So you people are saying that the educational system is designed to control what people can UNDERSTAND and people without degrees are supposed to doubt their own intelligence.
Sorry guys, skyscrapers are nothing but middle school physics. You must talk people into believing that they are stupid to make them believe the official story.
Curious how our educators can’t create something as simple as a National Recommended Reading List. But I suppose that would be bad for our Education BUSINESS. Too many people would learn too much without our Dumb Educators. The 9/11 Affair is their problem also. Children who started 1st grade in 2001 have now entered college. All of that time being educated and they can’t figure out what skyscrapers must do to hold themselves up. :smack:
Gotta maintain that intellectual Authoritarianism.
Actually science fiction has gotten really stupid since Star Wars. That’s it the Force brought the buildings down so fast.
psik
Yeah, if you just say, “global collapse ensued” without explaining it you can’t be contradicting much of anything.
ROFLMAO
http://911research.wtc7.net/essays/nist/
How do you explain “ensued” without mass distribution when every level had to be strong enough to support all of the weight above? Just leave the information out and expect everyone to BELIEVE.
psik
And where are your calculations on how the Conservation of Momentum affected the velocity due to that increase in mass along with how much energy was lost breaking the supports that had to be there to hold that mass against gravity for 28 years?
Oh yeah, how can you compute that if you don’t know the mass on each level? Hasn’t someone around here been asking for that information?
So why don’t you build a physical model that can completely collapse and demonstrate what you claim could happen? I built one with the supports tested to be as weak as possible to hold the static load. That is why I used paper loops, to be WEAK. IT STILL ARRESTED!
4 washers divided by 33 washers meant 12% by height. But the washers were not all of equal weight and I sorted them with the heaviest toward the bottom so they were less than 12% of the mass.
psik
How old is structural engineering? What changed in the late 19th century was the ability to produce steel cheap enough in large quantities. So skyscrapers became possible. The square cube law goes back to Galileo nearly 400 years.
The Empire State Building was completed in 1931, before the discovery of the neutron and long before the invention of computers and transistors.
You can doubt your intelligence and ability to comprehend middle school physics all you want. You should know more about your limitations than I do.
But I expect anyone waving a degree in structural engineering who claims the top of the north tower could fall straight down and destroy the rest to be able to provide steel and concrete distribution data and an experimental demonstration. Why should experts object to PROVING what they say? Structural engineering was not required at the school where I took electrical engineering.
psik
No. They simply have established in the rest of the paper that the dead load the building was able to support is now a live load that it quite obviously cannot. Most people understand this concept and it isn’t NIST’s fault that you cannot.
I tested one. It was too strong relative to my static load.
Curious that no engineering school has done a much heavier model than mine. That would give greater control of the crushable supports relative to the loads at each level.
A really good model would be at least 45 kilograms/100 pounds. But if we don’t have accurate distribution of mass data on the north tower than how can a model with the same distribution of mass be made?
psik
YAWN!
25 seconds is the collapse time counting the remains of the core referred to as, The Spire, that became visible after the cloud of dust dissipated for the last 5 seconds. So most of the building came down in significantly less time than that. There are various estimates based on seismic data.
The minimum possible time would be 9.2 seconds based on complete free fall acceleration in a vacuum. 11 seconds is not much more. So the time range for most of the mass coming down is somewhere between 11 and 20 seconds.
Suppose we had the north tower intact and then removed 5 stories, 91 through 95. That would leave a 60 foot gap with 15 stories in the air without support. They would fall. They would take 1.9 seconds to hit the top of the lower 90 stories and be travelling at 42 mph or 62 ft/sec.
Those 90 stories would be about 1080 feet tall. If the falling 15 stories could maintain a constant velocity while crushing six times as many stories as themselves even though they had to get stronger and heavier down the building than the falling 15 stories, then it would take 17.4 seconds to destroy 90 stories. That would yield a total of 19.3 seconds to destroy the north tower. So the distributions of mass in steel and concrete and calculations on the energy required to crush/break/destroy each level and how it had to affect collapse time would have to be taken into account in order to avoid the accusation of belief based on ignorance.
But Dr. Sunder of the NIST told NPR in a podcast the the north tower collapsed in 11 seconds.
These days a lot of high school kids should be able to write computer programs that compute collapse times strictly due to the Conservation of Momentum. Simulate 109 masses floating in space 12 feet apart supported by nothing. Drop the top 14 and compute the results of collisions. If the masses are equal it takes 11.9 seconds. Making the distribution bottom heavy can increase the time to 14 seconds.
We are supposed to believe that 11 seconds was possible when the physics profession has not demanded and provided accurate data on the distributions of steel and concrete down the north tower?
But after 12 years we do have a HUGE PSYCHOLOGICAL ISSUE. All of the people who have said the collapse was physically possible would look really STUPID if it were proven that it was not. So any insults or name calling do not move me in the slightest.
Anybody that wants to can ridicule my washers and paper loops all they want. I readily admit a bigger and heavier physics model to demonstrate collapse would be better. I have even suggested that a 3D printer be used to produce really accurate models of the north tower to be tested. But I don’t see any decent models either physical or virtual from any of the engineering schools that charge $20,000+ annually for tuition and teach structural engineering. After 12 years they would look silly too. But what do they actually do? THEY SAY NOTHING! What school has officially come out in support of the government position?
Provide a link please. LOL
In fact they would look somewhat silly if they made a model that could collapse because they could have done it in 2002 IF IT IS POSSIBLE. Why didn’t they do it then instead of allowing 12 years of pompous confusion. Because that is how people who just make pronouncements sound. The nation that put men on the Moon can’t supply 232 numbers specifying the tons of steel and tons of concrete on every level of buildings designed before 1969. That makes so much sense.
So as far as I am concerned the 9/11 Affair is the most scientifically hilarious incident in history. The longer it lasts the funnier it gets.
You can talk about ignorance all you want. What would it say about this entire site if collapse was proven impossible? LOL
So why not just PROVE that it was possible with models and be done with it? But if all you have is talk…
psikActually it was welding that made skyscrapers possible.
Don’t put words in my mouth.
As per your previous posting history, you have once again misconstrued others’ posts, completely missed the point, and decided to throw out your own mistaken theory.
No, the educational system is not a system of control. It is a system of education (fancy that!).
To date, the vast majority (90+%) of the people who are actually educated and trained in civil engineering and other fields related to skyscrapers and how they may collapse agree there’s nothing inherently wrong with NIST explanation for the events of 9/11/2001. In fact, all the available facts support that explanation quite well.
The vast majority of laypeople also agree with this.
If there’s any plausible controversy remaining, it has to do with the motivations of the attackers and who was ultimately responsible, not the physical sequence of events. And even the alternate scenarios of shadowy government conspiracies to put those men on the planes are far-fetched.
Why did I make the distinction between lay people and experts? No, it’s not meant to control the flow of information or argue from authority. It’s because the experts are actually educated and are less apt to make a mistake in analysis. Rather than relying on their authority, you can CHECK THEIR WORK! And people have. It’s small wonder that the people who do find fault with it are correlated highly with people who are less trained/educated in that sort of work. That would be suggestive of something to most people. Not you, apparently.
Over the course of the last several years, you have shown nothing that contradicts their work. All you have done is decried rather good models of the attacks while advocating your own bizarre toothpick/washer model of skyscrapers that is fractally wrong.
No, the physics aren’t so complicated nobody else can understand them. Nobody denies that. What we, in particular, deny is YOUR ability to understand them, and you yourself have provided considerable ammunition to shoot your own foot in this regard.
ETA: I now realize this post is just ridiculously long. Asimov wept. No, YOUR ignorance is not as good as THEIR knowledge. I sympathize. Few people wish to acknowledge their own ignorance, but that doesn’t give you a free pass to declare the laws of physics work the way you say their do.
LOL!
This is completely irrelevant to the post to which I responded. You claimed the pancaking was (shorthand) 13% vs. 87% all the way down, whereas both Tomndebb and I patiently explained to you it’s (13%+.9%) vs (87%-.9%) for the second floor impacted, (13.9%+.9%) vs (86.1%-.9%) for the third floor impacted, repeating all the way down.
Do you understand this? I mean, from a purely intellectual view, do you grasp the concept? As the “cap” fell, it accumulated the mass of the debris below it, and the building below the “cap” lost the mass that was now part of the falling cap.
Calculating the conservation of momentum doesn’t matter. It didn’t matter for the Tunguska event. It doesn’t matter for car crash analysis. It doesn’t matter for the WTC.
Pulling a random citation out of the interwebs we find that a tower weighs 450 million kg. If you divide that number by 116 (number of floors + basement levels), you get 3.9million kg per floor.
Obviously the top floors didn’t weigh this much, given that the bottom floors needed more structural support as to hold the weight of the rest of the building… so, wanna divide that number by 2*? Say the 100th floor of the WTC weighed (empty) 1.9 million kg? (4.2 million pounds)?
15 floors collapsed.
15*4,200,000 = 63,000,000 pounds.
Psikey, when you remove the structural support for 63,000,000 pounds and drop it on a building, what do you expect to happen? To me, the “Conservation of Momentum” principle strongly indicates that the damned 63 million pounds is going to go straight down.
And, again, we saw this happen. Twice. Where is the confusion?
I’m still working through this whole insistence on calculating momentums.
Correct me if I’m wrong, but it appears psikeyhackr is trying to apply inelastic momentum calculations to a rather elastic situation.
Is that the case? If so, wow, it adds a whole new dimension of wrongness to the whole thing.
Again…
We don’t have to prove anything with models. We saw the experiment. Twice. We saw two similar planes crash into two similar buildings resulting in the same collapse.
And the really dumb thing is the following:
The South tower was the second one hit, but the first one to fall. Why? Because the plane struck the South tower lower than where the North tower was hit.
Basic physics - there was a lot more weight above the impact site in the South Tower than above the impact site of the North tower. Ergo, the South tower fell first.
Again, this is what we would expect to happen in a basic physics experiment. It’s what we saw happen live and on TV. The weakening tower that had to support 25 floors fell before the one that had to support 15 floors, as one would expect (and calculate.)
So, again… WHAT IS THE CONFUSION?
It seems psikeyhackr is going back to that nonsensical 'It should fall like a tree!!!" that we heard back in 2006, side-by-side with ‘clunkity-clunk’.
ROFLMAO
You think a situation where steel is being bent and concrete is being broken can be elastic? I think you better look up what they mean.
http://hyperphysics.phy-astr.gsu.edu/hbase/elacol.html
The elastic situation is like Newton’s Cradle.
psikStop avoiding the question.
Where is the confusion in this? Why do you doubt all that you saw that day? You saw an experiment, repeated, resulting in the same outcome. Why do you doubt the outcomes?
Your failed attempts to model the collapse is useless, given that we already modeled the collapse, twice, on September 11, 2001. So, please, take your washers and toilet paper tubes home, never to be referenced again, because they are totally irrelevant.
Every floor did not have to be strong enough to support all the weight above - that weight was on the columns, not the floors. The floors of the WTC could support their own weight plus some safety factor more. When you had the top 15 floors (or whatever) of the North Tower come crashing down onto floor 94, that’s way more than the floor supports can withstand, so it fails. Then the top 16 floors come crashing down onto floor 93, and it fails. Then the top 17 floors come crashing down onto floor 92, and it fails. And so on…
Meanwhile, the perimeter columns, which were being held in a vertical orientation by the floor joists, suddenly had no lateral support, and there was an avalanche of debris pushing them outwards, so they quickly broke off and fell to the outside of the building as the avalanche continued downward. The core columns were stronger and had lateral support from each other, so were able to stand longer. Still, they depended on the connections to the perimeter columns to the floor joists to stay standing upright, and they then fell as well.
The reason that the investigators just said “global collapse ensued” is that all this is bleeding obvious to anyone who can think clearly.
By the way, several years ago I did the calculations you’re looking for, modeling the momentum of each floor. I made the approximation that each floor was about the same weight, which is a good approximation from what we know to be true. The collapse time I calculated was 14 to 15 seconds. By the way, I did all that in Excel, it’s not that hard.
And North was stuck pretty much dead-on whereas South was struck off-center. Causing the portion above the hole to fall to one side until gravity brought the whole thing downward.
AFAIK, the Tower roofs played a significant part in load bearing so once the roofs were compromised, there was no way the Towers were going to continue standing.