Outside energy had to be introduced for the twin towers to collapse the way they did

The only real question that remains (and will remain) unanswered is - are these (l)OSers merely trolls or are they really poor unfortunates who just can't see beyond their noses.
Either way, I fear the truthers are their wasting time.
Peace to all mankind.

Originally posted by samuisteve
The only real question that remains (and will remain) unanswered is - are these (l)OSers merely trolls or are they really poor unfortunates who just can't see beyond their noses.
Either way, I fear the truthers are their wasting time.
Peace to all mankind.

Seriously, I don't mean to break decorum, but cut the #.

Stop assuming that everyone that disagrees is wrong. It is another viewpoint. Respect it like I respect yours. What you do is say "I believe the evidence supports this, this, and this," and then the other side will say "I think the evidence really supports this, and this rather than those."

You never hear intelligent people saying "I believe this, and if you don't, you must be intentionally wrong."

So, really. Stop posting nonsense like that. It contributes nothing.

I've noted a lot of similarities here between the creationism versus evolution arguments. Truthers, like creationists, are obsessed with trying to pick holes in the OS, or with latching onto any kind of uncertainty in the OS, even though we cannot replicate the collapse, do not have all of the information, and are talking about an event that was completely chaotic.

Truthers really don't like to put their own theories forward, however, because if they were put to the same scrutiny as the OS, they would fall apart in seconds.

reply to post by humphreysjim


here's some math and physics. "T"=top floors of the tower "B"=bottom floors. "x"= the coefficient of resistance that each floor has. it actually increases as the floors go down, but we'll err heavily on the OS side, and say it's the same for all floors, and that the fire didn't weaken the upper floors at all (heat rises). so in short, "x" is the amount of punishment a floor can take before it is destroyed.

newton's third law means that for every action, there is an equal and opposite reaction. velocity doesn't effect the outcome since the force on both the top and bottom floors is equal.

the plane impacted wtc 1 from floor 92-98, so what the hell, lets just say 20 and above are defined as "T". 90 and below are "B". wtc 1 was 110 stories tall.

our equation looks like this:

Tx-Bx=?

if the result is positive, it means there was enough force/mass for the top floors to destroy the bottom floors without themselves being destroyed (what we witnessed).
a negative means the top floors should have been pulverized because the bottom floors could resist more than the top could dish out.

ok, so we have 20x-90x=-70. hmm, odd. newton's third law seems to be broken if x=x. this means there was either more resistance in the upper floors than the whole rest of the tower (greater than 4 or 5 times as a rough estimate factoring in the increased resistance) or most resistance in the bottom floors was removed.

since "x" DOES equal "x", we have to conclude that resistance was removed by an outside energy force. truthers would say thermate/explosives or something similar. we all agree that there should be a new independent investigation because it just doesn't add up.

for all we know it could have been koalas with blowtorches, but we DO know that resistance was removed.

this is the point where you either a) realize your wrong like i did, b) cover your ears and shout "i can't hear you" or c) say my analysis is "wrong/simplistic" without showing how it is wrong or inaccurate.

your move.

reply to post by Bob Sholtz


So where are the floors that have already failed in your "model"?

Originally posted by spy66

If you think the floors pancaked to the ground a head of the falling vertical support structure, Or at that the floors and the vertical support structure collapsed at the same time. You have a big issue with explaining the lack of resistance do to acceleration/fall time.

1. If the floors grave away and pancaked before the core and the walls. The floors must have fallen without resistance.

The floors did in fact fall "first", but not ahead of the free falling debris. There was small resistance from the truss ends' seats. The floors and a section of the top of the building came down, pushing out the exterior columns as well.

2. If the floors, the vertical support structure and walls collapsed at the same time. That means the structure was in tacked when the top section fell on the bottom section. The bottom section would have put up a lot more resistance and the acceleration speed from the top would not increase.

I'm not sure what you mean by this, but, The floors were coming down first, and then we later see the exterior columns being pushed out and away by the force of the collapse. The core came down last, as we see in the "spire" and the core from the South Tower. The lower section of the South Tower remained while the top section's core stayed with the top section. The top came down on the lower floor, dislodging it, and then crashing down to the one below. And so on and so on until they reached bottom. Each floor's "vertical support" was the same in regards to the floor truss's seats.

You must be viewing the whole integrity of the structure all wrong if you think the bottom section could give away this easy.

Or people imagine that falling "debris" from the top section acts as one large mass pushing against the bottom section at once!

The bottom section's floors had no vertical load carrying ability. Each floor was designed to hold its static weight with its safety factor. It was not ready for a dynamic force impacting it that was way over its design loads. For each floor this was true. and yes, the top section debris did help push down on the structure, but the floors were already falling once thier connections to the columns were severed, either by impact sheering or when the exterior columns were being pushed out like a banana by the top section.

reply to post by -PLB-


i counted all of them as falling. as i said, i err'd heavily on the side of the OS, counting the failed floors as both being there, AND providing space to fall.

but that is of no consequence, because you offer no argument, unless you want me to lessen the size of "T" to 12ish.

your goose is cooked,
the cabbage is done,
you're on the run,
this is no fun,
but it must be done.

the fire was too cold,
the OS is crap,
what can i tell you,
except shut your trap?

mmm, i'm actually pretty good at this. that took 75 seconds. *note to mods: i couldn't find anything else to rhyme, i mean no disrespect to PLB in my silly...whatever*

reply to post by -PLB-




I know you dont see past your own theory PLB. So lets just leave it, There will never be any progress with your mind included here.

If you dont see that if you drop 1000 lbs weight on a floor that is tied together with multiple connection points that can hold 500 lbs in weight. You dont have the capacity to understand how the 1000 lbs is actually putting its down force on multiple connections at the same time.

-If 1000 lbs land on a floor with 4 connections that can hold 500 lbs each. You have to do some critical thinking.

Ass soon as the 1000 lbs hit the floor, the 1000 lbs are putting down force on 4 connection. So if 4 connection are 500 lbs each. You have a total strength of 2000 lbs. Your 1000 lbs will just put a nice dent in the concrete floor.

The floor will not collapse.

If the 1000 lbs hit one of the sides with just two connections. You have two connection points that are 500 lbs each, that = 1000 lbs. What are the odds of the floor collapsing?


I have to add. If a connection is rated to hold 500 lbs there is a safety margin involved. Called SWL.
The connection will not break at 500 lbs. But at a 1000 lbs for instance.

A 500 lbs connection, means you can safely load 500 lbs onto it. But you should not over load it with 550 lbs for instance. Even though it can hold a load of 1000 lbs without problems.

reply to post by waypastvne


This is completely wrong, you put the rubble height where the lobby columns split:



___________________________________________________________________________



Even here you can see that the rubble is actually a bit piled up against the perimeter, creating a depression in the center of the footprint.

___________________________________________________________________________________

This image has a perspective problem making it seem that the rubble pile is higher than it is. Imagine yourself looking at that pile edge on, where would it come too? Exactly where the other image shows...




This is the correct height:





You can get a sense of the lobby and basement levels:

In order to find the potential energy of the tower, you definitely need to do an integral. That's because there are is evenly distributed mass, but the the height increases as you go up the tower...
the integral would look something like the integral from the bottom to the top, of [g(mass/ft)x]dx

or if the tower was 10 feet tall, at 10 g per foot it would be, the the integral from 0 to 10 of [9.8(10)x]dx. 9.8 times 10 times x(the height)

going to school for engineering right now... so I do calculus based physics

reply to post by Bob Sholtz


So what do you think happens to your "equal and opposite reaction" when there are failed floors between the top and lower section?

reply to post by spy66


I think you are missing the point that the load a single floor had to endure was magnitudes greater than the load capacity of all the connections of that floor combined. Redistributing loads to already overloaded connections is not going to be useful.

But the main question remains. On what exactly do you base that the resistance was lower than it should be?

Originally posted by Bob Sholtz
reply to post by humphreysjim

 

here's some math and physics. "T"=top floors of the tower "B"=bottom floors. "x"= the coefficient of resistance that each floor has. it actually increases as the floors go down, but we'll err heavily on the OS side, and say it's the same for all floors, and that the fire didn't weaken the upper floors at all (heat rises). so in short, "x" is the amount of punishment a floor can take before it is destroyed.

newton's third law means that for every action, there is an equal and opposite reaction. velocity doesn't effect the outcome since the force on both the top and bottom floors is equal.

the plane impacted wtc 1 from floor 92-98, so what the hell, lets just say 20 and above are defined as "T". 90 and below are "B". wtc 1 was 110 stories tall.

our equation looks like this:

Tx-Bx=?

if the result is positive, it means there was enough force/mass for the top floors to destroy the bottom floors without themselves being destroyed (what we witnessed).
a negative means the top floors should have been pulverized because the bottom floors could resist more than the top could dish out.

ok, so we have 20x-90x=-70. hmm, odd. newton's third law seems to be broken if x=x. this means there was either more resistance in the upper floors than the whole rest of the tower (greater than 4 or 5 times as a rough estimate factoring in the increased resistance) or most resistance in the bottom floors was removed.

since "x" DOES equal "x", we have to conclude that resistance was removed by an outside energy force. truthers would say thermate/explosives or something similar. we all agree that there should be a new independent investigation because it just doesn't add up.

for all we know it could have been koalas with blowtorches, but we DO know that resistance was removed.

this is the point where you either a) realize your wrong like i did, b) cover your ears and shout "i can't hear you" or c) say my analysis is "wrong/simplistic" without showing how it is wrong or inaccurate.

your move.

edit on 21-9-2011 by Bob Sholtz because: (no reason given)

Right BOB please show us your calculation for the impact force for the 31 floors of the South Tower when they drop ONE floor onto the floors below or the top 15 floors of the North Tower or you can try this little experiment I have suggested to others like you on here.

Get the heaviest weight you can hold without droping it (you should manage 50kg) get someone to hold it 12 feet above you (wtc floor height) they drop it and you catch it. Now make sure someone videos that put it on youtube with the address to send the flowers to!

Just to give you an idea of the forces possible, a little calculator for you have a go link at the bottom

Tell you what lets try some figs for the 50kg weight challenge

height 3.66 mtr
weight 50kg
gravity 9.8 m/s2
distance traveled lets say you slow it down over 4" thats about 100mm or 0.1 mtrs

Pop the figs in answer 17934 n now 10 n in a kilogram so divide by ten 1793.4kg YES 1.7934 TONS!!!

lets say you slow it down over 0.5 mtrs answer 3586.8 n divide by ten for kilograms equals 358.68kg more than 1/3 OF A TON!

SO ARE YOU UP FOR THE CHALLENGE (please remember to get the video done!!!!)

Or why dont you stick in figs for one floor slab at 700 tons or 700,000 kg slowed down by the thickness of the angle iron that held it against the walls (say 20mm of 0.02 mtrs) or the 5/8" bolts (16mm or 0.016 mtrs) that held it on the angle iron. The most likely objects to fail under the impact!


www.livephysics.com...

And you people think there wasn't enough force to bring the building down!

You see Bob this is a DYNAMIC LOAD something you obviously dont have a clue about!

reply to post by -PLB-

I think you are missing the point that the load a single floor had to endure was magnitudes greater than the load capacity of all the connections of that floor combined. Redistributing loads to already overloaded connections is not going to be useful.

If you have two "floors" with the same strength and mass hitting each other: What happens when that takes place?
-Do you get reduced falling speed or an acceleration of falling speed at impact point?

The connection points to the floor in the top section weren't stronger built than the connection points to the floors it hit on the section below. Regardless of the weight of the entire top section falling. Because the floor connections of the top section had the same strength as the once they hit bellow. That means the floor connections in the top section would also break do to resistance encountered when it hit the floor under it, and do the push from the falling mass of the top section "Core and walls".

I also have to add. That these floors were built to hold down force (people and furniture and so on) not up force. So the floor falling down onto the floor under would break of before the floor under. So they were not actually equal in strength. But for simplicity we can call then equal



The top section came straight down. That means core against core, wall against wall and floor against floor.

As you companion mentioned in a post earlier; He stated that the floors fell ahead of the rest of the building "core and walls".
Do you agree?

If you do, you have to explain how two "floors" with the same strength hitting each other will accelerate and gather mass, and than fall a head of a much larger constant falling mass "core and walls".

I have to stress the collapse time.

But the main question remains. On what exactly do you base that the resistance was lower than it should be?

What i am saying is that the top section that fell wasn't stronger built than the bottom section it hit.
They were equal in strength but their mass was different, because one was in motion and the other stationary. The top section had a much lower mass than the bottom section it hit. But the bottom section was built to hold the stationary mass of the top section.

I dont know if you can see the resistance involved here?

If one floor from the top section hit one floor from the bottom section, i am saying that you have two floors with the same strength hitting each other. That means you have great resistance at impact point and reduction in fall speed. Until the next floor comes and hits. But when that floor comes, it is hitting a greater mass because it is now hitting two floors with lower speed. In other words more resistance.

Originally posted by spy66
If you have two "floors" with the same strength and mass hitting each other: What happens when that takes place?
-Do you get reduced falling speed or an acceleration of falling speed at impact point?

If the falling floor is still intact it would likely fail and reduce in speed. The top section would not. It would reduce in acceleration though.

The connection points to the floor in the top section weren't stronger built than the connection points to the floors it hit on the section below. Regardless of the weight of the entire top section falling. Because the floor connections of the top section had the same strength as the once they hit bellow. That means the floor connections in the top section would also break do to resistance encountered when it hit the floor under it, and do the push from the falling mass of the top section "Core and walls".

An intact floor impacting with an intact floor only happens right after collapse initiation. After that it will be already failed floors impacting with intact floors. The intact floors in the lower section will have the failed floors plus the top section falling on it.

The top section came straight down. That means core against core, wall against wall and floor against floor.

It did not come straight down, it tilted. It is physically impossible that the core or walls of top and lower section fell exactly on top of each other.

As you companion mentioned in a post earlier; He stated that the floors fell ahead of the rest of the building "core and walls".
Do you agree?

Yes, I also said that.

If you do, you have to explain how two "floors" with the same strength hitting each other will accelerate and gather mass, and than fall a head of a much larger constant falling mass "core and walls".

I have to stress the collapse time.

Again, intact floors were not hitting each other, except for the first impact after initiation. All subsequent impacts were already failed floors impacting the lower floors. (The reaction I usually get when I explain this is that the failed floors almost completely ejected, which is a completely unsubstantiated claim unsupported and contradicted by physics).

What i am saying is that the top section that fell wasn't stronger built than the bottom section it hit.
They were equal in strength but their mass was different, because one was in motion and the other stationary. The top section had a much lower mass than the bottom section it hit. But the bottom section was built to hold the stationary mass of the top section.

I dont know if you can see the resistance involved here?

If one floor from the top section hit one floor from the bottom section, i am saying that you have two floors with the same strength hitting each other. That means you have great resistance at impact point and reduction in fall speed. Until the next floor comes and hits. But when that floor comes, it is hitting a greater mass because it is now hitting two floors with lower speed. In other words more resistance.

The failed floor add to the falling mass. Not to the mass of the stationary lower section. So the crushing mass increases. And the speed also increases as result of gravity accelerating the mass. So both mass and speed increased. The result is that momentum increased. And the next intact floor in the lower section will have to endure an even larger load than the floor before it.

reply to post by -PLB-

If the falling floor is still intact it would likely fail and reduce in speed. The top section would not. It would reduce in acceleration though.

The thing is the top section would also loos speed because the floors are connected to it. Until they break of.

The entire top section would loose speed because the whole thing is hitting the bottom section.

An intact floor impacting with an intact floor only happens right after collapse initiation. After that it will be already failed floors impacting with intact floors. The intact floors in the lower section will have the failed floors plus the top section falling on it.

You have watched to many 3d animations.

-Does debris a broken of floor have the same impact mass/force as a intact structure does?

- Each floor is constructed/designed to hold down force not up force. Would that have any impact on the intact top section hitting the bottom section?

-The core is designed to hold up and down force. Wouldn't that create resistance that would slow down the top section?

-The walls are designed to hold up/down force. Wouldn't that create resistance that would slow down the top section?

Now i have to stress the collapse time.

It did not come straight down, it tilted. It is physically impossible that the core or walls of top and lower section fell exactly on top of each other.

Wrong. It was the vertical support structure between the top and bottom section that collapsed. So the building must have fallen onto its own vertical support structure. That is why it tilted to one side. So don't come and tell me fairy tails. You can even see this on all the YouTube videos that the building came straight down and than tilted.

Explain how you came to the conclusion that the top section pushed down the bottom section?

reply to post by -PLB-

If the falling floor is still intact it would likely fail and reduce in speed. The top section would not. It would reduce in acceleration though.

You just say that, but on what basis?

Can we have a little evidence for this?

Even in the best case for the OS analogues, dominoes and avalanches, the material causing the local collapse undergoes deceleration.

FORCE is a function of MASS and ACCELERATION. Both object are being subjected to the same FORCE. Since the mass of upper section is unchanged and, because the structure are similar, they are of roughly the same local mass at least in the initial impacts, they must undergo the same acceleration.

Since the lower portion was already resisting acceleration in the collapse direction to the value that the upper body is being accelerated at the impact force it is being subjected to must be greater than the force causing gravitational acceleration of said mass, otherwise it would not cause the lower structure to fail.

That means that the upper body must be subjected to a force greater than the force causing IT to be accelerated.

That means that the resistance (in the form of the normal force the lower structure is able to generate) is greater than the force of gravity.

That means that the upper structure must be decelerating.

_____________________________________________________________________________________________

Okay, that was terribly verbose and dense reasoning, but the fact of the matter is that this behavior is observed in every single natural collapse event and gravity induced demolition, but not explosive demolition.

The only way that it can carry on accelerating is if the the lower structure were somehow weakened so that it could no longer support the upper.

Again, PLB reveals himself as a truther, because saying that the acceleration decreased but did not become negative is saying that gravity alone was not the cause and that external energy was introduced.

Unless you have some evidence you are not showing PLB? Some physical experiment you may have performed that proves me wrong?

reply to post by wmd_2008


LoL.

The top section was not dropped on top of the bottom section dude

And for how long are you able to hold 50kg above your head before you have to let it go? lol.

Do you think the 50kg would crush you to the ground if you dropped it on your head lol?

If you drop it. You are not built to hold 50kg above your head

Jesse's no wonder people can be fooled to believe this NIST report.

Originally posted by spy66
The thing is the top section would also loos speed because the floors are connected to it. Until they break of.

The entire top section would loose speed because the whole thing is hitting the bottom section.

The weight of the top section is much greater than the supports of a single floor can carry. When resistance is lower than gravitational load it means there is acceleration.

You have watched to many 3d animations.

-Does debris a broken of floor have the same impact mass/force as a intact structure does?

- Each floor is constructed/designed to hold down force not up force. Would that have any impact on the intact top section hitting the bottom section?

-The core is designed to hold up and down force. Wouldn't that create resistance that would slow down the top section?

-The walls are designed to hold up/down force. Wouldn't that create resistance that would slow down the top section?

-It will probably be different. (what is your point?)
-It probably will. (what is your point?)
-It would offer resistance limited by the floor connections.
-It would not slow down, but decrease acceleration.

Now i have to stress the collapse time.

Wrong. It was the vertical support structure between the top and bottom section that collapsed. So the building must have fallen onto its own vertical support structure. That is why it tilted to one side. So don't come and tell me fairy tails. You can even see this on all the YouTube videos that the building came straight down and than tilted.

Explain how you came to the conclusion that the top section pushed down the bottom section?

No, the top section did not fall on the lower support structure. This is an extremely unrealistic scenario, even impossible when there is tilt. But even without tilt, its like throwing a stool from 2 meters high on top of another stool that is upside down, with the legs damaged and twisted. Its not going to happen.

Originally posted by Darkwing01
You just say that, but on what basis?

Can we have a little evidence for this?

Its simple physics. Lets be generous and say the load capacity of a floor is 5 times its weight. Mass falling down is at least 12 times the floors weight. So the gravitational force is greater than the load capacity. In other words, it will accelerate, as there is a net downwards force.

Even in the best case for the OS analogues, dominoes and avalanches, the material causing the local collapse undergoes deceleration.

Sure, there will be local and momentary deceleration of pieces of debris hitting an intact floor.

FORCE is a function of MASS and ACCELERATION. Both object are being subjected to the same FORCE. Since the mass of upper section is unchanged and, because the structure are similar, they are of roughly the same local mass at least in the initial impacts, they must undergo the same acceleration.

Since the lower portion was already resisting acceleration in the collapse direction to the value that the upper body is being accelerated at the impact force it is being subjected to must be greater than the force causing gravitational acceleration of said mass, otherwise it would not cause the lower structure to fail.

That means that the upper body must be subjected to a force greater than the force causing IT to be accelerated.

That means that the resistance (in the form of the normal force the lower structure is able to generate) is greater than the force of gravity.

That means that the upper structure must be decelerating.

This is not correct. The resistance of the floor is, generously, 5 times its own weight. The weight falling on it was at least 12 times the weight of a floor. So there is a net acceleration as result of gravity. Would you have placed the mass carefully on the floor instead of dropping it, the floor would also have failed and there would also have been acceleration. No impact forces here.

Okay, that was terribly verbose and dense reasoning, but the fact of the matter is that this behavior is observed in every single natural collapse event and gravity induced demolition, but not explosive demolition.

The only way that it can carry on accelerating is if the the lower structure were somehow weakened so that it could no longer support the upper.

Again, PLB reveals himself as a truther, because saying that the acceleration decreased but did not become negative is saying that gravity alone was not the cause and that external energy was introduced.

Unless you have some evidence you are not showing PLB? Some physical experiment you may have performed that proves me wrong?

Since your reasoning above was wrong, your conclusions here are of course also wrong. Note that I have kept it as simple as possible, in reality there would of course be other factors which I ignored.