Why a one-way Crush down is not possible

[phunk]

Topic link. So we have the steel frame of the building behaving apparently rather strangely on 9/11, but in a somewhat consistent manner. When an apparent aircraft flies into the steel frame building it does not seem to decelerate inside the building. If the object that flew out the other side was not the nose (the nose was the apparent shape) but an engine, then the engine actually accelerated whilst inside the building.

Or, as any sane person might conclude, the engine did not accelerate while in the building, but just didn't decelerate as much as the other parts.

 

[alienentity]

Continued off topic followed by more drivel

[snip]



Vertical crush down collapse topic. When the top load suddenly falls on the intact tower below (by whatever process, exploding pancake, tiredness, magic) it crushes down the building in an amazing low resistance manner. Even though the WTC2 top load disintegrated upwards faster than it could fall downwards and the top was more weakly constructed than the tower below that it was theoretically impacting. So, the "gathering snowball effect" theory is that 40% of the top load was ejected outside the tower footprint during the first couple of seconds of the collapse process when the top load disintegrated. This left 60% of the normal static weight (mass x gravity) of a loosely arranged "snowball of disassembled building components" falling as a dynamic "heavy rain" load on the intact, redundantly over-engineered and very robust tower below. Not falling as a contiguous robust "sledgehammer load", but as heavy rain. Not like as a "sandbag" dropped from the top of a building on the head of an unsuspecting person below, but as the contents of a sandbag dropped from the top of a building. What is the difference? An intact sandbag would kill you, break lots of bones in your body, but loose dry sand falling on you would put sand down the back of your neck and probably only irritate you.

So when the WTC2 tipped-over-top disintegrated upwards faster than it could fall down, it did so explosively, which is to say stuff flew in all directions at once, up, down and sideways. The ripple-down explosive collapse process below the exploding top, in the initial stages, was also faster than the now disassembled top-load components could keep up, as they fell out of the sky, 40% outside of the tower footprint. It is difficult for me to see how gravity alone could achieve all of these strange effects. The hypothesised gravity motivated "heavy rain snowball" was evidently not causing the ripple down explosive collapse process, or causing the apparently explosive (presumably mistimed) squibs even lower down the tower than the main rapidly descending demolition wave front. How did the hypothetical "heavy rain" break the lateral floor connections between the core columns and perimeter columns so easily? Or break out the "barrel banding effect" of the perimeter column tube, or crush down the core columns, or crush the concrete etc. in such an apparently effortless resistance-free manner in such a short time frame? I really do not know but I think that the distortion of space called "gravity" only really supplied the energy to get the already disassembled, by some other energy means, building down to the ground.

[snip]

Andrew, your post was still responding to O/T subject, whatever excuse you gave. Just couldn't help yourself I guess.

Moving along... in a nutshell, regarding your crushdown comments; your assumptions are largely unsupported by hard evidence, your physics analogies are false.

Hence your conclusion is wrong. I'm not going to waste time and space going into any further detail.

 

[alienentity]

Or, as any sane person might conclude, the engine did not accelerate while in the building, but just didn't decelerate as much as the other parts.

It's OT anyway. Who really cares what Andrew thinks? I don't.

 

[Heiwa]

It seems this thread Why a one-way Crush down is not possible of the WTC 1 or any structure (small top crushing big bottom) has developed into a discussion about what happened to same structure, if it were crushed by an object laterally, e.g. a plane full of fuel (and people) up top at impact speed about 200 m/s. The vertical crush down is only initiated at 8.5 m/s, but let's compare lateral/vertical impacts.

Say lateral object has mass m and then the energy applied laterally on the wall is 20000m Joule. BANG! Quite a lot. It was applied on about 100 m² of the wall and it made a hole in the structure and unknown damages inside.

Now, let's say that upper part of WTC 1 has mass 400m that drops on lower part at 8.5 m/s. How much energy is involved? Yes, it is 144500m Joule. It is thus >7 times more but applied on a much bigger surface (4000 m²).

So lateral impact was 20000m Joule on 100 m² or 200m J/m² and the vertical impact later was 144500m Joule on 4000 m² or 36m J/m² or 5-6x less.

Everybody seems to agree that the lateral object with mass m arriving at 200 m/s stopped inside the structure (and then some fraction of m (fuel) caught fire). So the structure stopped it.

As Joule is same as Newton(force)meter, we find that the structure could stop 200m N/m laterally but not 36m N/m vertically.

The structure appears to be stronger laterally than vertically! Just some food for thought.

Actually, as this is not the case, it is another example Why a one-way Crush down is not possible.

 

[alienentity]

Everybody seems to agree that the lateral object with mass m arriving at 200 m/s stopped inside the structure (and then some fraction of m (fuel) caught fire). So the structure stopped it.

No, they don't. It has already been determined, unambiguously, that more massive and dense parts of the planes continued thru the towers, even after colliding with structure, and in fact ended up on NYC streets. These would include engines and landing gear.

Also, in fact, the fuel itself traveled thru the building, carrying so much energy that it managed to not only damage the internal structure but also make it to the opposite side and exit.

So your understanding is just plain wrong. It's no wonder you have difficulty coming to the right conclusions.

 

[Heiwa]

No, they don't. It has already been determined, unambiguously, that more massive and dense parts of the planes continued thru the towers, even after colliding with structure, and in fact ended up on NYC streets. These would include engines and landing gear.

Also, in fact, the fuel itself traveled thru the building, carrying so much energy that it managed to not only damage the internal structure but also make it to the opposite side and exit.

So your understanding is just plain wrong. It's no wonder you have difficulty coming to the right conclusions.

So how much of m went through and was not stopped? 5%? Engines and landing gear is maybe 0.05m? What could mass be of that famous noose that came out and disappeared that FOX edited away?

 

[Dave Rogers]

However, the lack of a loss of momentum on the Nose Out video would still be a problem if the "nose" were something else from a genuinely video recorded "material object" aircraft, rather than the nose. The pixel shape was apparently of the "nose leaving the WTC2 north face unscathed", without slowing down inside the building, not of an engine which would have been behind the nose and should have exited the building later anyway.

Having actually done some velocity analysis on the Chopper 5 video, I can state categorically that you are incorrect here. It's quite a simple matter to track the movement of the plane from frame to frame of the video, project its course to the far side of the tower, and extrapolate its position had the tower not been there, and the emerging object is a long way behind this position. It's also quite simple to determine that the airliner is moving at 26 pixels per frame prior to impact, and that the ejected object is moving at 6.5 pixels per frame, or about a quarter of the speed.

http://www.internationalskeptics.com/forums/showthread.php?t=82280 has further discussion.

The quick "fade to black" part of the theory was that the video did not actually keep running, because the terrorists made a semi-live "Wag the Dog" type video error during the 17-second time delay. Which the terrorists, in charge of this "shock and awe media propaganda narrative", corrected by the quick fade-to-black, when they spotted the unfortunate SNAFU "nose out" problem developing.

A crucial problem with this theory is that, as I understand it, the Chopper 5 feed was not shown live on 9/11. The live feed shown was from Chopper 7. Therefore, the theory being proposed is that the conspirators had a video clip that showed a compositing error, that was not shown live, but subsequently shown with a simple fade-to-black added a few frames too late to remove the error. This places too great a burden of incompetence on the conspirators, who could simply have cut a few more frames before releasing the clip for broadcast without arousing suspicion.

Dave

 

[AndrewIlluminatus]

Topic link. So we have the steel frame of the building behaving apparently rather strangely on 9/11, but in a somewhat consistent manner. When an apparent aircraft flies into the steel frame building it does not seem to decelerate inside the building. If the object that flew out the other side was not the nose (the nose was the apparent shape) but an engine, then the engine actually accelerated whilst inside the building.

Or, as any sane person might conclude, the engine did not accelerate while in the building, but just didn't decelerate as much as the other parts.

In the hypothetical vertical crush down hypothesis (not actually supported by empirical observation of the video data IMO) impact of the top ductile steel-frame block into the bigger/stronger bottom ductile steel-frame block IMO should result in some deceleration of the smaller/weaker top. The "engine of the movement" of the top block down is the distortion of space called "gravity", created by the mass of the planet existing in space and the standing start acceleration on offer for the top block, from gravity, is about 32ft/s/s at around sea level.

This weird video aircraft business is about a horizontal impact of a moving vehicle into a stationary steel-frame building. The aircraft was said to be moving at a final impact velocity considerably higher than the standing start acceleration on offer to the top block through gravity of course. Nevertheless, I suggest that when an aircraft impacts and penetrates a ductile steel frame building, it should start to decelerate and disintegrate (just as I would expect the falling top block to decelerate on impact).

Now the "nose" of the aircraft is the front end of the aircraft, I hope we can agree. When the helicopter video was examined in a frame by frame manner by the "Nose Out" theorists, it was found that the "image of the nose" of the UA175 object did not decelerate during the apparent passage of the "aircraft" whilst it was hypothetically inside WTC2. If the UA175 aircraft image was therefore a computer generated image (CGI) of an aircraft (not a video of the genuine impacting material object aircraft) then the "nose out" event reappeared at precisely the correct moment in time and in precisely the correct shape for it to be the "undamaged nose". The very soft nose of a then evidently video fraudulent CGI aircraft, that did not apparently decelerate or suffer any damage from impacting and penetrating and transiting the interior of the tower. The "nose" did not accelerate whilst "inside the tower" but neither did it decelerate. Therefore, if you wish to postulate that an engine transited the interior of the tower and the "nose out" is not the "nose" but the engine, then the "engine" (if a genuine material object) self-evidently must have exited the tower a little too soon. The engines being located under the wings further back down the aircraft than the nose. The fade to black was carried out perhaps just in time to avoid the embarrassment of not only the nose getting through the building unscathed but the wings, engines and possibly even the tail doing the same thing (major FUBAR). This of course also means that if a genuine aircraft hit the tower in the video and the "nose out" artefact was a genuine engine instead, then the engine must have accelerated inside the tower instead of decelerating (as I would expect). For this reason I cannot accept your proposition "as any sane person might conclude, the engine did not accelerate while in the building, but just didn't decelerate as much as the other parts" as having much merit.

Here is a list of strangely different UA175 impact speeds issued from official bodies that were presumably calculated using various different bits of official video footage of the WTC2 strike:
Massachusetts Institute of Technology - 503 mph / 436 knots / M0.653
British Royal Air Force - 575 mph / 500 knots / M0.750
Federal Aviation Administration - 586 mph / 510 knots / M0.765
National Institute of Standards and Technology - 546 mph / 475 knots / M0.714
Federal Emergency Management Agency - 590 mph / 514 knots / M0.771
http://web.mit.edu/civenv/wtc/PDFfiles/Chapter III Aircraft speed.pdf
Eduardo Kausel, MIT – "the above data indicates that the terrorists flew towards the WTC close to the ground at nearly the full cruising speed of the planes, which is about 900 km/h (560 mph) at a normal altitude of 10km (33,000 feet). It is surprising that the inexperienced pilots that the terrorists were could still steer the planes at those speeds and hit their target head on. Also, considering that the air at low altitudes is much denser than that at normal cruising height, the pilots greatly exceeded Vne ("Velocity Never Exceed") and thereby risked disintegration of the aircraft by air friction."

Ahem, cough, cough!

 

[Dave Rogers]

Now the "nose" of the aircraft is the front end of the aircraft, I hope we can agree. When the helicopter video was examined in a frame by frame manner by the "Nose Out" theorists, it was found that the "image of the nose" of the UA175 object did not decelerate during the apparent passage of the "aircraft" whilst it was hypothetically inside WTC2. If the UA175 aircraft image was therefore a computer generated image (CGI) of an aircraft (not a video of the genuine impacting material object aircraft) then the "nose out" event reappeared at precisely the correct moment in time and in precisely the correct shape for it to be the "undamaged nose".

As I just pointed out, this is untrue, and demonstrably so. The ejected object was both visually distinguishable from the nose of the airliner, exited at a significantly later time than the expected time for an object moving at constant speed (from my notes I've found it emerged seven frames later than expected), and was moving at a quarter of the speed. This hasn't been disputed by Ace Baker, who advanced a more complicated and absurdly impractical theory to account for it. I can go through what he claimed later if I have time, but it would actually have made the video synching considerably more difficult than using very much simpler methods.

Since your premise is incorrect on this point, could I suggest you re-evaluate your conclusion?

Dave

 

[AndrewIlluminatus]

Since your premise is incorrect on this point, could I suggest you re-evaluate your conclusion?
Dave

If you are correct about the video frame rate and that video was not live on 9/11 anyway then I agree that this theory looks more like a naughty post 9/11 hoax.

 

[AndrewIlluminatus]

LOL. This is a joke right? People like andrew don't EVER do that.

I am not actually terribly emotionally attached to any particular theory if that is what you think. Primarily because I suspect a great deal of fraud is going on in one way or another. For the dialectic to work the narrative generators need to create both a Thesis and Antithesis and I am rather more intrigued by the idea of what their intended Synthesis might be. As I said earlier: "It looks to me rather like either a massively important video fraud happened on 9/11 itself, or a relatively minor video fraud has happened since 9/11, by some mischievous troublemakers. I do not know and I cannot know which theory is correct, because video is obviously not very reliable as a form of evidence."

 

[Dave Rogers]

If you are correct about the video frame rate and that video was not live on 9/11 anyway then I agree that this theory looks more like a naughty post 9/11 hoax.

But it isn't anything of the sort. It's a misinterpretation of a well-understood phenomenon that someone with a mental illness has sincerely advanced as a genuinely-held belief about what happened on 9/11. Ace Baker is very committed, totally serious, and quite unwell.

Dave

 

[alienentity]

In the hypothetical vertical crush down hypothesis (not actually supported by empirical observation of the video data IMO) impact of the top ductile steel-frame block into the bigger/stronger bottom ductile steel-frame block IMO should result in some deceleration of the smaller/weaker top. The "engine of the movement" of the top block down is the distortion of space called "gravity", created by the mass of the planet existing in space and the standing start acceleration on offer for the top block, from gravity, is about 32ft/s/s at around sea level.

This weird video aircraft business is about a horizontal impact of a moving vehicle into a stationary steel-frame building. The aircraft was said to be moving at a final impact velocity considerably higher than the standing start acceleration on offer to the top block through gravity of course. Nevertheless, I suggest that when an aircraft impacts and penetrates a ductile steel frame building, it should start to decelerate and disintegrate (just as I would expect the falling top block to decelerate on impact).

Now the "nose" of the aircraft is the front end of the aircraft, I hope we can agree. When the helicopter video was examined in a frame by frame manner by the "Nose Out" theorists, it was found that the "image of the nose" of the UA175 object did not decelerate during the apparent passage of the "aircraft" whilst it was hypothetically inside WTC2. If the UA175 aircraft image was therefore a computer generated image (CGI) of an aircraft (not a video of the genuine impacting material object aircraft) then the "nose out" event reappeared at precisely the correct moment in time and in precisely the correct shape for it to be the "undamaged nose". The very soft nose of a then evidently video fraudulent CGI aircraft, that did not apparently decelerate or suffer any damage from impacting and penetrating and transiting the interior of the tower. The "nose" did not accelerate whilst "inside the tower" but neither did it decelerate. Therefore, if you wish to postulate that an engine transited the interior of the tower and the "nose out" is not the "nose" but the engine, then the "engine" (if a genuine material object) self-evidently must have exited the tower a little too soon. The engines being located under the wings further back down the aircraft than the nose. The fade to black was carried out perhaps just in time to avoid the embarrassment of not only the nose getting through the building unscathed but the wings, engines and possibly even the tail doing the same thing (major FUBAR). This of course also means that if a genuine aircraft hit the tower in the video and the "nose out" artefact was a genuine engine instead, then the engine must have accelerated inside the tower instead of decelerating (as I would expect). For this reason I cannot accept your proposition "as any sane person might conclude, the engine did not accelerate while in the building, but just didn't decelerate as much as the other parts" as having much merit.

Here is a list of strangely different UA175 impact speeds issued from official bodies that were presumably calculated using various different bits of official video footage of the WTC2 strike:
Massachusetts Institute of Technology - 503 mph / 436 knots / M0.653
British Royal Air Force - 575 mph / 500 knots / M0.750
Federal Aviation Administration - 586 mph / 510 knots / M0.765
National Institute of Standards and Technology - 546 mph / 475 knots / M0.714
Federal Emergency Management Agency - 590 mph / 514 knots / M0.771
http://web.mit.edu/civenv/wtc/PDFfiles/Chapter III Aircraft speed.pdf
Eduardo Kausel, MIT – "the above data indicates that the terrorists flew towards the WTC close to the ground at nearly the full cruising speed of the planes, which is about 900 km/h (560 mph) at a normal altitude of 10km (33,000 feet). It is surprising that the inexperienced pilots that the terrorists were could still steer the planes at those speeds and hit their target head on. Also, considering that the air at low altitudes is much denser than that at normal cruising height, the pilots greatly exceeded Vne ("Velocity Never Exceed") and thereby risked disintegration of the aircraft by air friction."

Ahem, cough, cough!

Andrew. You've derailed the thread AGAIN, one day after the MOD warning.

What's this thread about, again? Andrew? Andrew? Is there anybody home?

 

[AndrewIlluminatus]

What's this thread about, again? Andrew? Andrew? Is there anybody home?

Objects involved in a collision (or continuously resistant and disintegrating collisions) normally decelerate, along with whatever motivational energy is involved being converted into some other kind of work?

Which is faster, driving a heavy car flat-out downhill through a field of corn or down a smooth highway next to the field? The car engine keeps working either way, just as the "engine of gravity" keeps working in the "vertical crush down" and, by driving downhill, gravity is also assisting the motion of the car in this thought experiment. My guess is that driving downhill through the field of corn must take considerably longer than driving down the road, as the car has to use up motivational energy (and will thus decelerate) in doing a lot of extra work to get the corn out of the way. The hypothetical top load of the tower, as a moving vehicle, if it had been on wheels, would have found more resistance to its movement if it had been rolling downhill through a field of corn! Than through the still intact and highly robust (in comparison to corn) steel-frame tower below it. If it had been a combine harvester gathering in the corn to add to the weight of the machine as it rolled downhill it would have nevertheless have taken longer. How long "should" the tower have taken to collapse explosively via gravity and kinetic energy? Forever in my opinion, because it should not have collapsed like that at all.
Topic link. Heiwa: "It seems this thread Why a one-way Crush down is not possible of the WTC 1 or any structure (small top crushing big bottom) has developed into a discussion about what happened to same structure, if it were crushed by an object laterally, e.g. a plane full of fuel (and people) up top at impact speed about 200 m/s. The vertical crush down is only initiated at 8.5 m/s, but let's compare lateral/vertical impacts."

 

[beachnut]

... How long "should" the tower have taken to collapse explosively via gravity and kinetic energy? Forever in my opinion, because it should not have collapsed like that at all. ...

12.08 seconds for the higher impacted tower. Simple momentum model matches the initial collapse time.

I think of JFK and the moon when I see failed science and delusion like your ideas based on your own biased failed common sense. We do these things "not because they are easy, but because they are hard,". Taking physics is harder than regurgitating failed ideas of 911Truth like you do. JFK knew it is hard to step up to the knowledge needed to understand systems. You pathetically support anti-intellectual tripe without understanding or using physics.

The towers fell in times consistent with the momentum transfer. One tower fell in about 12.08 seconds exactly like the model of a momentum transfer. It is simple physics and math.

The worst part of your delusion is ignoring the facts and evidence. You should have asked the Chief Structural Engineer of the WTC towers; he agrees with me and only some people spewing delusions agree with your failed ideas on the WTC towers collapse.

The simple model closely matches the initial collapse time; did you realize a portion of the core was still standing for over 20 seconds. Did you know people survived in the core? Not sure with all your delusions on explosives why no one at the WTC was blown up? No thermite burns either.

Your opinion the towers should still be standing is a failed ideas based on your what? Lack of knowledge? You have no training in Physics so how can you make an educated guess on the WTC? Why have you failed so badly at understanding the WTC towers falling? Why can't you support the OP?

Did someone tell you the dust was mostly ceiling tiles, wallboard (gyp board), insulation, fire insulation, and just dust; not concrete? This makes Hoffman's stuff idiotic junk science. At least you are not alone with the delusions and Heiwa, and Bill Smith are trying to compete with you for the dumbest ideas in physics and engineering on things about 911. Good luck, I think you can win this contest to see who can accelerate faster than free-fall down the pit of 911Truth ignorance.

AI you have to be able to calculate something if you are going to claim your ideas are true. You can't, so why are you spreading lies, false information, hearsay, and delusions?

 

[alienentity]

Objects involved in a collision (or continuously resistant and disintegrating collisions) normally decelerate, along with whatever motivational energy is involved being converted into some other kind of work?

[/I]

Look Andrew. Here's Heiwa's original post, ok?
'Many persons take for granted that steel structures of certain types, e.g. WTC Twin Towers, collapse from top down - one-way crush down - if you start a fire up top. The fire is supposed to weaken support steel structure up top and then the structure above displaces down and one-way crushes the complete steel structure below.
Bazant and Zhou explained this already 2 days after 911.
However, the one-way crush down process is not possible under any circumstances.'

It wasn't about planes. If you want to make believe it is, you're in lala land.


And, in response to your comment about deceleration, you're spot on: the towers fell at LESS than freefall speed, due to the resistance of the building structures.

Call it deceleration if that's the way you view it. Case closed. End of story.

Next issue.

 

[Heiwa]

The towers fell in times consistent with the momentum transfer. One tower fell in about 12.08 seconds exactly like the model of a momentum transfer. It is simple physics and math.

The simple model closely matches the initial collapse time; did you realize a portion of the core was still standing for over 20 seconds. Did you know people survived in the core? Not sure with all your delusions on explosives why no one at the WTC was blown up? No thermite burns either.

Good, back on topic Why a one-way Crush down is not possible.

So momentum transfer suddenly makes one-way crush down possible of a small part C of a bigger part A of same structure? Simple physics and math?

Say A = 10C

OK, C transfers with its velocity v (8.52 m/s) a certain momentum to A, but what is A doing in turn with this momentum? Transfers it to ground! Right.

Assume C has mass m and A has mass 10m. The momentum of C is mv (kgm/s), so the velocity of A after momentum transfer is only 0.1v or 0.852 m/s. That's not a lot!

Then A transfers the momentum to ground with a very big mass so the velocity of ground is virtually zero.

Simple physics and math.

Where is the one-way crush down due to momentum transfer?

Aha, A was not strong enough to transfer the C momentum mv to ground!

But THAT should be easy to demonstrate. Just produce a structure A that is not strong enough to transmit a momentum transfered to it from a similar structure C smaller in size, e.g. 1/10A but same internal structure.

You'll find that C is not strong enough to do it (even with a hat truss, if that matters)!

Now I take a month vaccation or what it is. Real work? See you end May.

 

[phil76]

A little experience :

Take 4 steel tubes, put them vertically so they form a square.
Take several square sheets of paper and attach them to the steel tubes at equal distance (for example one sheet at height/10, one sheet at 2xheight/10, and so on) .
Take an object which weight is higher than the weight that can be supported by the connections between your sheets of paper and your column.
Let fall your object on the uppermost sheet of paper from a distance equal to the distance between your sheets of paper....

Does your construction hold or do you observe a "one way crush down" ? Do the sheets of paper slow the fall of your object ?

 

[Dave Rogers]

What we saw on 9/11 was the opposite of that, the demolition wave on WTC2, at the start, shot down, symmetrically, faster than the asymmetrical load and tipped top load (already explosively demolished) could keep up with the fall.

Again, this is factually incorrect, and demonstrably so to anyone who has seen videos and photographs of the collapse. Have you actually done so, and had you been told what to see before you did?

Dave

 

[phil76]

Andrew, I am French, so I am not "a mind-controlled American" (not meant as an insult toward americans) . It doesn't makes me a truther and it doesn't make me think that there is something suspect in the way the towers fell.

Steel strutures are very strong, but contrary to other structures they are also very "fragile" (meaning that when they fail, the failure is almost instantaneous).