[extracted] New(?) 9-11 stuff
KSM got a plea deal. The guy who supposedly masterminded the 9/11 attacks is not getting the death penalty.
If you still
I've read the paper. I can't really comment on the crux of his argument, which is that I guess he says the building should have offered more resistance(?), but as far as timings go, he appears to be focusing only on the first 4 seconds of the collapse event, which he analyses in some detail. Unless I've missed something, he gives no overall collapse time or any analysis thereof
Unless the acceleration suddenly becomes non-uniform, the measured acceleration of 6.31 m/s2 can be extrapolated for the full course.
The bottom of the upper 12 floor pile driver hits the ground after 98 floors:
s = 98 x 12.0 feet = 1176 feet = 358 m.
Giving a collapse time of 10.6 s.
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Ok, as we get into the analysis on page 10, the author says this:I am really struggling with this statement. He claims that the forces in the interaction are equal and opposite, but I'm not sure they cancel out in the way he claims, because they are acting on different objects. Mechanics never was my strong point, so I'm probably misunderstanding something, but this just doesn'
By Newton's second law the resultant force is mg - N, the normal reaction is N and the weight is mg.
By measurement the acceleration is of magnitude 6.31 m/s2, which is 0.64g. So the resultant force is 0.64mg.
Therefore the normal reaction force is 0.36mg. Or 36% of the pile driver block weight.
The third law pair of the normal reaction and the force of the pile driver on its counterpart is equal in magnitude i.e. 0.36mg.
His argument is thus: the force needed to both pulverise the lower floors and accelerate the block is lacking by circa 90%, citing safety coefficients for what the structure is built to withstand. Hinting at controlled demo etc. (Controlled demo has no supporting evidence ofc).
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Hey wimp, you posted again without addressing the problems with your theory or the question of why you disagree with the video evidence of collapse times (do try to resist the urge to commit the argument from authority fallacy on this one again please).
Hey wimp, you posted again without addressing the problems with your theory or the question of why you disagree with the video evidence of collapse times (do try to resist the urge to commit the argument from authority fallacy on this one again please).
Video evidence of collapse times: see Chandler.
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Video evidence of collapse times: see Chandler.
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Oh look you posted again without addressing my questions or the problems with your theory.
That's a very wimpy thing to do.
I'm not interested in chandlers opinion, I'm interested in yours.
I presented to you clear video evidence that the collapse times are not what you say they are.
You have refused to address this literally dozens of times now.
One might think that is a wimpy thing to do.
Do better.
Unless the acceleration suddenly becomes non-uniform, the measured acceleration of 6.31 m/s2 can be extrapolated for the full course.The bottom of the upper 12 floor pile driver hits the ground after 98 floors:s = 98 x 12.0 feet = 1176 feet = 358 m.Giving a collapse time of 10.6 s.In any reasonable collapse model the upper block never reaches the ground unless it pulverises 98
I don't know why we need to keep repeating the same thing dozens of times before you understand - in the video of the event, we observe the collapse time to be at least 15 seconds. When you said he analysed the video, I thought there would be an explanation of what he thinks the start and end points of the collapse are and we could see where this 10 second time comes from, preferably with a start and end frame. There is not. See Gorgo's post showing a large part of the building still intact after 11 seconds. I'm going to go with what I can see with my own eyes over this model using simplifying assumptions and extrapolations.
If you want me to adopt this collapse time number you will have to explain to me how a large part of the building remains standing after the collapse is supposedly complete.
By Newton's second law the resultant force is mg - N, the normal reaction is N and the weight is mg.By measurement the acceleration is of magnitude 6.31 m/s2, which is 0.64g. So the resultant force is 0.64mg.Therefore the normal reaction force is 0.36mg. Or 36% of the pile driver block weight.The third law pair of the normal reaction and the force of the pile driver on its coun
I'm sorry, I just don't understand this argument. Probably being a bit thick. But it's not important was far as timings go.
Unless the acceleration suddenly becomes non-uniform, the measured acceleration of 6.31 m/s2 can be extrapolated for the full course.The bottom of the upper 12 floor pile driver hits the ground after 98 floors:s = 98 x 12.0 feet = 1176 feet = 358 m.Giving a collapse time of 10.6 s.In any reasonable collapse model the upper block never reaches the ground unless it pulverises 98
I'm not going through all this but sqrt(2d/g) with d = 110 * 3.8m and g = 6.81m/s^-1 gives a time of 11.4s. With d = 95*3.8m it gives 10.7s. I don't know where 10.6s comes from.
By Newton's second law the resultant force is mg - N, the normal reaction is N and the weight is mg.By measurement the acceleration is of magnitude 6.31 m/s2, which is 0.64g. So the resultant force is 0.64mg.Therefore the normal reaction force is 0.36mg. Or 36% of the pile driver block weight.The third law pair of the normal reaction and the force of the pile driver on its coun
To be a little more clear:
The system is accelerating as a whole due to the resultant force which is the weight minus the normal reaction.
The pile driving upper 12 floors block and its target do indeed act on different objects. Let A = pile driver on target. Let B = target on pile driver. A acts on B and B acts on A, with forces equal in magnitude and opposite in direction as per newtons 3rd law. No relative acceleration is caused here, i.e. the block and target are coupled together and hence acclerate at the same rate. The force of the pile driver on the target is therefore 0.36mg.
"Why would the pile driver upper block exert a force smaller than its static weight and accelerate?" Is the right question. It is the question Chandler is asking.
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Oops multiple new posts without addressing the multiple issues with your theory and why you disagree with the video evidence of collapse times much longer than 12 seconds.
Surely it was just your 56th oversight in a row and you are not just a complete wimp.
To be a little more clear:The system is accelerating as a whole due to the resultant force which is the weight minus the normal reaction.The pile driving upper 12 floors block and its target do indeed act on different objects. Let A = pile driver on target. Let B = target on pile driver. A acts on B and B acts on A, with forces equal in magnitude and opposite in direction as pe
Ok I mean I'd need to spend more time than I want to to fully understand this. But if his model says the building should collapse in under 11 seconds, and we see with our own eyes that it takes 15 seconds or longer, then the model is clearly wrong. I mean, don't get me wrong, it might still be correct for some things, just not for collapse time. Unless he or you can address why the model does not reconcile with what we can see in reality.
"All models are wrong. Some are useful." - some guy whose name I forget.
Why does it take dozens of times of repeating the same thing to get it into your thick head Billy? First we had it with the exterior panels, now we have the same pattern emerging with the model collapse times disagreeing with what we see in reality.
And just to be clear, this isn't us looking at a pile of rubble and saying "well it doesn't look like 1.8m tonnes". This is an event where you can pause the video and see for yourself that at the time the model claims the event has completed, it has not completed, and in fact goes on for at least another 4 seconds. There is little room for subjectivity. Unless someone can provide a persuasive explanation why the model is correct and this basic objective analysis is wrong, which nobody has even attempted to do.
To be a little more clear:The system is accelerating as a whole due to the resultant force which is the weight minus the normal reaction.The pile driving upper 12 floors block and its target do indeed act on different objects. Let A = pile driver on target. Let B = target on pile driver. A acts on B and B acts on A, with forces equal in magnitude and opposite in direction as pe
Here is a thread with responses to some of Chandler's claims:
Why does it take dozens of times of repeating the same thing to get it into your thick head Billy? First we had it with the exterior panels, now we have the same pattern emerging with the model collapse times disagreeing with what we see in reality.And just to be clear, this isn't us looking at a pile of rubble and saying "well it doesn't look like 1.8m tonnes". This is an even
Billy used to tell us over and over again that we should trust what we actually SEE!
He used to emphasize that principle while posting his pics.
Now he no longer posts pics, and we're supposed to believe models instead of what we see with our own eyes.
I'm very confused!!! (To be fair, I'm very easily confused.)
I think what Flatty is claiming is that the buildings felll at speeds faster than freefall and that would be impossible if the building collapsed only under its own weight. It would seem he believes the forces in the opposite direction would also “slow down” the collapse and that another source of force must be present, such as controlled demolition, to explain the collapse at the speed of near freefall. Or space lasers.
But since he never answers questions or says anything sensical, this is just a guess.
I think what Flatty is claiming is that the buildings felll at speeds faster than freefall and that would be impossible if the building collapsed only under its own weight. It would seem he believes the forces in the opposite direction would also “slow down” the collapse and that another source of force must be present, such as controlled demolition, to explain th
He doesn't believe they fell at all. He believes they got dustified by space lasers. So he's been trying to prove that they can't have fallen, because they "collapsed" faster than the laws of physics would allow. The only problem is that it is complete and utter horseshit, because he claims they collapsed in 12 seconds or less (NIST and other sources have in fact given figures that comport with this claim, but these figures are clearly incorrect), but video of the event unequivocally shows it was 15 seconds or more. He is debunking a strawman, essentially.
Actual engineers and qualified experts that have discussed Chandler's paper are not kind, for the record.
https://internationalskeptics.com/forums...
Chandler does make some pretty basic errors (eg not differentiating between a static and dynamic load), so it's not surprising. I can see why billy likes him.
Actual engineers and qualified experts that have discussed Chandler's paper are not kind, for the record.
https://internationalskeptics.com/forums...
Chandler does make some pretty basic errors (eg not differentiating between a static and dynamic load), so it's not surprising. I can see why billy likes him.
Yeah, according to this thread, looks like the part I intuitively found suspect is in fact total horseshit.
Yes! That massive object falling faster and faster, will not hurt you because it exerts a force less than its own static weight on you when it hits you! So hang in there, big objects falling are kind of weightless as I learned from David, the physics expert of all time, now moving into delusions, insanity, and fiction.
If a 2000 pound car crushes you, it will not crush you if dropped from 10 feet because the force exerted as it hits you is less then its own static weight. It is in free-fall so it is weightless, no force at all, just use your index finger to push it aside and ....
Sarcasm from this poster, obvs, but this is also the part I could not reconcile in my mind. I was afraid it was because I was missing some basic principle of mechanics. Looks like I wasn't.
This poster also summarises it quite well:
The dumbest part of David's paper is the part where he says added mass will make the force less; as if F=ma was fictional, as David adds m, the F gets smaller
I now have a definitive calc for the collapse time based solely on available, irrefutable data.
1. Calculating the total height of the fall.
95% of the world trade centre was air, i.e. 5% solid material. 5% by volume gives 13.57% by area. The frontal surface area is therefore expected to squash down into a surface area of height 13.57% of the total height. 110 floors therefore collapse down to a height of
13.57% x 110 floors = 14.9 floors. Let us say 15 floors.
The upper 12 floor "pile driver", i.e. floors above the 98th floor combined as a single mass, fall through a height of
98 - 15 floors = 83 floors
before being impeded by the crushed mass beneath it.
Total tower height = 417 m.
417 m / 110 floors = 3.79 m/floor.
83 floors have a height
83 x 3.79 m = 314.57 m.
This is the height of the collapse.
2. Calculating the rate of acceleration.
Referring to extensive video analysis of the initial 4 seconds of collapse (see Chandler above) the acceleration is a uniform 6.31 m/s2.
3. Time, t
= sqrt(2s/a)
= 10 s (2 sf).
Consistent with times stated by NIST, Eagar and Bazant.
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I think what Flatty is claiming is that the buildings felll at speeds faster than freefall and that would be impossible if the building collapsed only under its own weight. It would seem he believes the forces in the opposite direction would also “slow down” the collapse and that another source of force must be present, such as controlled demolition, to explain the collapse a
More wrong than right in this post.
I will not bother to correct since you did not bother to be accurate.
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Yeah, according to this thread, looks like the part I intuitively found suspect is in fact total horseshit.
Sarcasm from this poster, obvs, but this is also the part I could not reconcile in my mind. I was afraid it was because I was missing some basic principle of mechanics. Looks like I wasn't.
Chandler was trying to expose the contradiction himself. Wasn't amazingly presented but with perseverence we see his point.
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