Mekt Ranzz's Challenge Thread

[Brainster]

Here is an example of where a typical layperson can go horribly astray when confronted with what he or she may assume to be an elementary physics problem. Au contraire!

Question: A 20-story building hangs suspended from a crane so that the bottom of the building is 10 feet directly above a 90-story building. Right next to this first 20-story building is another identical 20-story building suspended from another crane at an identical height above the ground, but with no building underneath it. Both cranes let go of their respective 20-story buildings at the same time. Which one hits the ground first?

Answer: This is actually a bit of a trick question.

Prior to 9/11/01, 100% of Advanced Physics Degree professionals would have agreed with the lesser-educated, "common sense" crowd and said that the building with nothing but air beneath it would strike the ground considerably faster than the other, which, quite honestly, could not really be expected to burrow its way through a 90-story building to reach the ground at all.

However, since 9/11/01, physicists have learned that the answer is actually "there will be virtually no difference in the rate of descent between the two 20-story buildings. They will both strike the ground essentially at the same time."

So you see, one must always consult one's local physics expert when questions concerning the physical universe arise. PLEASE DO NOT ATTEMPT TO WORK THROUGH ANY TYPE OF PHYSICS PROBLEMS ON YOUR OWN AT HOME—ALWAYS CONSULT A PROFESSIONAL. Only a professional knows which laws of physics are currently being applied to describe the physical universe that surrounds us. THESE PHYSICAL LAWS ARE SUBJECT TO CHANGE. Please do not assume you are up to date on the latest equations and/or theories concerning gravitation or conservation of energy and momentum.

You may now return to your regularly-scheduled life, knowing that you are safe in the good hands of the people who you expect to watch out for you and your family's best interests, since that would take too much time out of your day to do for yourself.

Brought to you by the "Have You Hugged Your Big Brother Today?" foundation.

Originally posted by tzo at 911Blogger.com

First, and most obviously, the building which has no building below it will hit the ground first.

But there are several obvious problems with applying this trivial analogy to the WTC collapses:

1. The assumption is that the towers collapsed in the same amount of time as it would have taken for the top sections to hit the ground unimpeded. This is wrong; the actual collapses appear to have taken 15 seconds or slightly longer; it is difficult to tell due to the rising dust cloud. It is true that several "official" sources claim the collapse times were 10 seconds and 8 seconds for the North Tower and South Tower respectively; these sources are wrong. (ETA: Or misinterpreted)

2. The assumption is that controlled demolition results in collapse in free-fall time. This assumption is never examined; I have yet to see a "Truther" who timed a controlled demolition and discovered that the acceleration was equal to g. Indeed, if you think about it, there is no reason that a building that was demolished by charges would come down in free-fall time, for the exact same reason highlighted in your example; parts of the building would provide some resistance to the force of gravity.

Say that you blow out all the columns in the fifth basement or wherever. So the fourth basement (and what's above it) falls at free fall acceleration for 12 feet. Then it stops and the remainder of the building would at least provide some resistance to collapsing, right? Not sufficient to arrest collapse, I assume, but certainly sufficient to provide some deceleration? The only way for this not to happen is to suppose that all the support inside the building is being eliminated everywhere at the same time; in other words, that there is no 90-story building below.

Use the video timer on any of the Google videos of the North Tower, and you will find that the 10 second estimate is plainly wrong. Try timing some of the collapses of controlled demolitions as well, and you will see that they do not come down in free fall.

It is very trivial to prove that the buildings did not come down in free fall acceleration; look at the debris field.

Welcome to the Forum, Mekt, always glad to see another comic book fan here!

 

[Brainache]

Are the Truthers reading that line in the NIST report that says something about the time for the first bits of debris to hit the ground and confusing it with the time of total collapse?

Seems I heard something to that effect once or twice...

 

[Minadin]

I don't think they're getting that far into the NIST report (if at all). The 9/11 Commission Report actually lists the collapse time for one of the towers at 10 seconds. I looked into it a bit, but I couldn't find what their source was for that figure.

 

[Brainster]

Are the Truthers reading that line in the NIST report that says something about the time for the first bits of debris to hit the ground and confusing it with the time of total collapse?

Good point, I should have said "are mistaken or misinterpreted". I know that the 9-11 Commission says that the South Tower collapse time was 10 seconds; not finding an estimate for the North Tower.

 

[Minadin]

I had posted a thread on collapse time claims a couple months ago with the things I had found . . . here it is:

http://www.internationalskeptics.com/forums/showthread.php?t=91415

If anyone wants to add to that thread or this one with any new information, that's still certainly something I'm interested in.

 

[T.A.M.]

Interestingly, the quote about the 10 seconds is referenced as 156...which if you go to the footnotes section, lists the reference as page 40 of appendix H of the progress NIST report.

Going to that location, the only info that matches the footnote information is the time of collapse at 9:58:59.

Interesting as well, but unrelated (I had never read this bit before) was the comments on the "molten material" seen dripping from the tower (the truthers thermite)...

H.7.2 Molten Material
It has been reported in the FEMA report (McAllister 2002) as well as in the media that what appeared to be molten metal was observed pouring from the north face near the northeast corner. This is the area where the sustained fires were seen. Video records and photographs indicate that the material first Interim Report on Evolution of WTC Fires Based on Image Analysis appeared at 9:51:52 a.m. and continued to pour intermittently from the building until the time of collapse.

Some of the material can be seen falling in Fig. H–21. Close-up video and photographs of the area where the material is pouring from have been examined and show that it is falling from near the top of window 80-256. The most likely explanation for this observation is that the material had originally pooled on the floor above, that is, floor 81, and that it was allowed to pour out of the building when this floor either pulled away from the outer spandrel or sank down to the point where the window was exposed. The fact that the material appears intermittently over a several minute period suggests that the
floor was giving way bit by bit.

The composition of the flowing material can only be the subject of speculation, but its behavior is consistent with it being molten aluminum. Visual evidence suggests that significant wreckage from the plane passed through the building and came to rest in the northeast corner of the tower in the vicinity of the location where the material is observed. Much of the structure of the Boeing 767 is formed from two aluminum alloys that have been identified as 2024 and 7075 and closely related alloys. These alloys do
not melt at a single temperature, but melt over a temperature range from the lower end of the range to the upper as the fraction of liquid increases. The Aluminum Association handbook (Aluminum Association 2003) lists the melting point ranges for the alloys as roughly 500 °C to 638 °C and 475 °C to 635 °C for alloys 2024 and 7075, respectively. These temperatures are well below those characteristic of fully developed fires (ca. 1,000 °C), and any aluminum present is likely to be at least partially melted by the intense fires in the area.

on page 38-39 of the document, found below...

http://wtc.nist.gov/progress_report_june04/appendixh.pdf
(caution...PDF)

TAM

 

[A W Smith]

Rance Muhammitz has not replied to this thread yet?

 

[pomeroo]

Rance Muhammitz has not replied to this thread yet?

Mekt Ranzz has made two discoveries familiar to many twoofers: 1) he is far from being the smartest person posting on this forum; 2) everybody has noticed that fact.

 

[T.A.M.]

FEMA's report also stated 8 and 10 seconds respectively, but it was based on the seismic data only...perhaps this is where a lot of the confusion over 8 and 10 seconds has come from.

FEMA Report on WTC Chapter 1, Page 1-9

TAM

Edit: Note, they have WTC2, which was struck much lower, as taking 10 second, but WTC1, struck much higher, as taking only 8 seconds, based on the seismic signal. They also have the WTC7 signal as lasting 18 SECONDS.

 

[PhantomWolf]

FEMA's report also stated 8 and 10 seconds respectively, but it was based on the seismic data only...perhaps this is where a lot of the confusion over 8 and 10 seconds has come from.

FEMA Report on WTC Chapter 1, Page 1-9

TAM

Edit: Note, they have WTC2, which was struck much lower, as taking 10 second, but WTC1, struck much higher, as taking only 8 seconds, based on the seismic signal. They also have the WTC7 signal as lasting 18 SECONDS.

You have to remember that the big shockwaves won't start until the debris start hitting the ground, 9-10 seconds after the collaspe started.

 

[T.A.M.]

I agree the more you actually READ what is being produced here, the more you realize it really has nothing to do with actual time of collapse, but I wonder if this table is not part of the problem (in addition to the NIST comments) that has lent to the 8 and 10 second comments.

The table (Table 1.1 Timeline of Major Events) is misleading, as next to the 10 second, (nd below it 8 second) "Signal Duration" listings, they have the words "WTC2 began collapsing", "WTC1 began collapsing". The table would have you think that these were the collapse times based on signal duration.

TAM

 

[A W Smith]

I agree the more you actually READ what is being produced here, the more you realize it really has nothing to do with actual time of collapse, but I wonder if this table is not part of the problem (in addition to the NIST comments) that has lent to the 8 and 10 second comments.

The table (Table 1.1 Timeline of Major Events) is misleading, as next to the 10 second, (nd below it 8 second) "Signal Duration" listings, they have the words "WTC2 began collapsing", "WTC1 began collapsing". The table would have you think that these were the collapse times based on signal duration.

TAM

Did anyone here actually time that video that has the large tree section of perimeter columns just about hitting the ground?

 

[Brainster]

Edit: Note, they have WTC2, which was struck much lower, as taking 10 second, but WTC1, struck much higher, as taking only 8 seconds, based on the seismic signal. They also have the WTC7 signal as lasting 18 SECONDS.

That actually makes sense if you think about it as the time that debris was hitting the ground; because there was more building above the collapse point in the South Tower, of course it would take a little longer for all of it to hit the ground from the initiation of hitting the ground (not from the initiation of collapse).

 

[1337m4n]

I don't think they're getting that far into the NIST report (if at all). The 9/11 Commission Report actually lists the collapse time for one of the towers at 10 seconds. I looked into it a bit, but I couldn't find what their source was for that figure.

What's mind-boggling is how whenever the 9/11 Commission Report or NIST support the Truthers' theories (in the case of the 10-second collapse time), they present it as ultimate proof, but in all other cases it is a pack of lies and not to be believed.

 

[T.A.M.]

That actually makes sense if you think about it as the time that debris was hitting the ground; because there was more building above the collapse point in the South Tower, of course it would take a little longer for all of it to hit the ground from the initiation of hitting the ground (not from the initiation of collapse).

SO are you saying that the seismic data, and its signal duration, represents the duration it took for the first of the top section to hit the ground, until the end of the collapse?

TAM

 

[defaultdotxbe]

What's mind-boggling is how whenever the 9/11 Commission Report or NIST support the Truthers' theories (in the case of the 10-second collapse time), they present it as ultimate proof, but in all other cases it is a pack of lies and not to be believed.

then when you point out that it took longer they say "if the comission report is wrong why do you support it" (another argument lifted right from the creationists BTW)

the interesting thing is that i always the creationists used that because they require inerrancy in the bible, so they assume anything that intends to disprove it must also be totally inerrant

but where does the CT requirement of inerrancy come from?

 

[Brainster]

Kick for Mekt, who's back.

 

[snagswolf]

The easiest way to prove the towers didn't fall at freefall speed, is to look at the videos and compare the speed of the towers' descent to the debris falling off of it, which WAS falling at freefall speed.