Physics of 9/11...

reply to post by hawkiye


its late and im confused. i'm arguing FOR the controlled demolition model. and i agree, the freefall speed demonstrated in the towers wouldn't be possible unless the supports were simultaniously destroyed.

the synopsis of my posts is thus :fire and the damage from the planes wasn't enough to bring down the towers. even if we toss out the melting point of steel, and the fact it was insulated against fire damage, and that the towers were designed specifically to withstand passenger aircraft impacts, the tops of the towers wouldn't have fallen straight down and crushed the rest of the tower at near free fall velocity. they would have either fallen to the side, or remained exactly where they were.

[edit on 25-6-2010 by Bob Sholtz]

Originally posted by jthomas

Originally posted by hawkiye
Great videos, great proof. And he is right on the money all other arguments are moot when you look at it from a laws of physics standpoint. It was a controlled demolition no question about it! All other suggested scenarios defy the laws of physics and have no precedent in history!
[edit on 23-6-2010 by hawkiye]

I think most people rely on the actual analysis rather than videos. There is no evidence that any "laws of physics" were violated.

Read the final NIST report and show us where they missed any violation of the laws of physics. It would seem, given that the evidence, methodology, expertise, and the total lack of any uproar by physicists, forensic scientists, and structural engineers worldwide, that your claim is not supported.

I have read the NIST report. When an object of mass hits another object of mass it stops temporarily causing a jolt. The building could not have free fallen with no jolts as it did hitting the lower undamaged floors. Watch the first video he expresses it much more succinctly then I and then proves it with experiments. Tell me where he is wrong. That is perhaps if not the best, one of the best videos I have seen on it. If you can refute it then you will have my attention.


[edit on 25-6-2010 by hawkiye]

Originally posted by Bob Sholtz
reply to post by hawkiye

 

its late and im confused. i'm arguing FOR the controlled demolition model. and i agree, the freefall speed demonstrated in the towers wouldn't be possible unless the supports were simultaniously destroyed.

My bad somehow when I read your post the towers toppling (rather then free falling) didn't register, sorry.

"However, for the upper part to shed over the side, rather than straight down, the lower part must *FIRST* halt the upper part. What he's saying, is that by taking the path straight down, it will encounter less resistance than if it is first halted, and then redirected over the side."

Sorry, I don't buy that. If you have this massive and very heavy upper part tipping over, nothing will halt it. Gravity, momentum and common sense dictate that it should continue to tip over and drop over the side of the building. The analysis of the upper part first having to be stopped by the lower part prior to tipping over makes no sense at all.

"Determining that it would NOT halt has been determined by several independent investigations by well published and scholarly structural engineers, structural engineering firms, and structural engineering professors and instructors."

I agree 100% with these studies. There is no reason for the top portion of the building to halt and it should have continued to tip over, broken off and fallen down the side of the building. Due to the asymmetrical damage to the tower, that is how any potential collapse should have played out and that should have been the maximum amount of damage incurred to the building. And even this scenario is quite a stretch, due to the immense strength of these buildings and the extremely high improbability of oxygen starved office fires compromising the structural integrity of numerous massive steel beams, 99% of which were not damaged.

When a vertical structure is leaning on an angle, it should continue to lean until gravity takes hold and forces it to the ground, in more or less a horizontal fashion. When a vertical structure is leaning this much, there is no way that it will right itself back to a vertical and upright position, unless its feet (support base) are pulled from under it, so to speak, by another force.

If the collapse of the upper portion of the tower was straight down from the beginning, then you can make an argument for a pancake collapse. But since the first part of the collapse consisted of this rather significant leaning motion, this makes the probability of a pancake collapse highly unlikely, if not impossible.

Another issue which also has not been sufficiently explained is what caused the destruction of the core of the building? Even if the building had pancaked, the core, for the most part, should have still been standing. There was nothing in those buildings that could have reduced those massive steel beams to dust, other than explosives, of course.

And if the steel beams were not reduced to dust, as some like to claim, those beams from the core should have been piled about 20 stories high after the collapse, which they obviously weren't. What kind of force could cause this type of complete and utter destruction?

I don't know, maybe we should start taking the PaperWeight Theory more seriously.

Originally posted by iamcpc

Originally posted by ANOK
First off there was no extra weight that the building was not designed to hold.

How do you know that? I think you're just making that up.

He knows that because the buildings were standing prior to the planes hitting. They therefore had "no extra weight" that they were not "designed to hold".

If they did have extra weight they were not designed to hold - as your theory claims - then by definition they wouldn't have held it.

Originally posted by Bob Sholtz
as for the "can senario", it is rubbish. yes, if you drop a brick onto a can of aluminum, it will get crushed straight down. try chopping the top 1/8th of the can off and dropping it onto the can, did it get crushed? see the problem? you are assuming even damage, which is wrong, and you are also dropping something that is much much much heavier than the can. since it takes 32.516 12 ounce aluminum cans to equal one pound, and the average cement block weighs about 40 lbs, in your senario, the tower was crushed by something that weighs 65 MILLION tons. silly person is silly =P

It's not rubbish when something drops with X force onto something that can support or resists 1/5x force.

Originally posted by Shadow Herder
As for the ridiculous analogy of the weightlifter and that the top fell from a great height destroying 70+floors to the base...Stupid.

Wtc 7 anyone? even the 2 towers come to mind

There should of been many floors left pancaked if these silly debunker logics were somewhat fathomable in the real world.

It seems that my post has been ignored. There is no way the top can come down and destroy 60+ more untouched floors without them being weakened. The top portion of the building appeared to be guided down.

In this next simulation you can see that the building cannot collapse entirely. But when the bottom supports are weakened then the building can collapse to the base. Ont he second run on the video you can see the small hand cursor removing support below the collapse.



[edit on 25-6-2010 by Shadow Herder]

Originally posted by hawkiye

Originally posted by Bob Sholtz
reply to post by Joey Canoli

 

i'm a certified structural welder. i see every day what happens to steel when it gets hot, when it melts, and when it bends. my analogy wasn't rocket science, it was a simple explanation of why the tower would topple over.
as i've stated, (and i think this actually applies more to the twin towers, because a relatively small office fire can't collapse a building) as the planes struck the towers, more damage would be done at the point of impact than any other part of the tower, specifically the side the plane crashed into. my earlier analogy comes into play, and of course, the tower would give in on the side that is weakest, toppleing that direction.

now, i would like for you to tell me where my train of thought is wrong, instead of replying with "you're not an engineer, so you can't say that".

Your train of thought is proven wrong in the first video. It defies the laws of physics. Had the towers collapsed as you surmise they would not have free fallen without obstruction as they did. They would have hit the lower undamaged floors and stopped. Did you watch the video? If so then maybe you can explain where he is wrong?

The twin towers did not free fall. Nice try.

www.plaguepuppy.net...

Notice free falling debri falling below the collapse????

THIS IS BECAUSE THE COLLAPSE IS SLOWER THAN FREE FALL SPEED!

Originally posted by FOXMULDER147

Originally posted by iamcpc

Originally posted by ANOK
First off there was no extra weight that the building was not designed to hold.

How do you know that? I think you're just making that up.

He knows that because the buildings were standing prior to the planes hitting. They therefore had "no extra weight" that they were not "designed to hold".

If they did have extra weight they were not designed to hold - as your theory claims - then by definition they wouldn't have held it.

Maybe you didn't notice but the towers collapsed.

Good video.

Note: Ad Hominem

"For the most part, the new level of discourteous activity is focused on an amazing amount of ad hominen personality attacks directed toward ATS Members, high-profile 9/11 "Truth" personalities, high-profile 9/11 "Debunker" personalities, and even non-public figures those who have been in the mainstream news as reported witnesses the events on 9/11/2001. This type of activity in the 9/11 Forum on AboveTopSecret.com stops now. "

Originally posted by SphinxMontreal

Another issue which also has not been sufficiently explained is what caused the destruction of the core of the building? Even if the building had pancaked, the core, for the most part, should have still been standing. There was nothing in those buildings that could have reduced those massive steel beams to dust, other than explosives, of course.

According to independant investigations it has been determined that a portion of the core support beams were destroyed in the airplane impacts.

Originally posted by iamcpc

The twin towers did not free fall. Nice try.



Notice free faling debri falling bellow the collapse????

Actually your wrong again. Nice try. The dusty sections did not appear to fall at free fall but the internal collapse was close to free fall.


[edit on 25-6-2010 by Shadow Herder]

Originally posted by iamcpc

Originally posted by FOXMULDER147

Originally posted by iamcpc

Originally posted by ANOK
First off there was no extra weight that the building was not designed to hold.

How do you know that? I think you're just making that up.

He knows that because the buildings were standing prior to the planes hitting. They therefore had "no extra weight" that they were not "designed to hold".

If they did have extra weight they were not designed to hold - as your theory claims - then by definition they wouldn't have held it.

Maybe you didn't notice but the towers collapsed.

What sort of moronic statement is that?

My post was perfectly clear. Here, I'll repeat - If the towers did have extra weight they were not designed to hold - as your theory claims - then by definition they wouldn't have held it.

They were standing fine before the planes hit! Ergo, they were not overloaded with weight.

In any case, your theory is complete nonsense. The "top" sections of the towers only fell a few storeys [the distance of the plane impact damage] onto the "bottom" sections - that distance is nowhere near far enough for the top sections to reach the momentum necessary to completely flatten both towers in 10 seconds.

(That's roughly freefall speed, BTW. In a vacuum.)

[edit on 25-6-2010 by FOXMULDER147]

Originally posted by hawkiye

When an object of mass hits another object of mass it stops temporarily causing a jolt.

I guess you have never dropped a cinderblock on a pop can.

The building could not have free fallen

The building did not free fall. If the whole argument of defying the laws of physics was based on the assumption that the twin towers fell at free fall speeds let me enlighten you. The twin towers fell slower than free fall speed.

www.plaguepuppy.net...

You can, very clearly, see debri falling at free fall speed next to the collapsing building.

Because the debri is free falling faster than the collapse (you know that it's falling faster than the collapse because the debri is falling next to undamaged, uncollapsed, portions of the buildings) then that is irrefutable evidence that shows that the twin towers collapsed SLOWER than free fall speed.

Originally posted by Bob Sholtz

....as the planes struck the towers, more damage would be done at the point of impact than any other part of the tower, specifically the side the plane crashed into. my earlier analogy comes into play, and of course, the tower would give in on the side that is weakest, toppleing that direction.

now, i would like for you to tell me where my train of thought is wrong, instead of replying with "you're not an engineer, so you can't say that".

I'd say that this train of thought would have been spot on IF and ONLY IF the tower would have collapsed immediately after the plane strikes.

However you use an important word above that I don't see you using in your complete analysis of why the collapse initiated.

Damage.

Specifically, fire damage. There is zero analysis on your part that I can see that attempts to ascertain exactly where loads got transferred as a result of the plane impact, nor do I see any attempt to quantify what was happening to the towers as a result of fire damage.

It MUST be acknowledged that fire damages steel's load carrying capacity. Therefore that MUST BE factored in.

Your attempt to nullify it by saying that no high rise steel framed building has ever collapsed due to fire is nothing but a charlatan's ruse. It is undeniable that steel suffers damage in fires alone that cause them to collapse. Therefore the canard of narrowing the scope to only high rises is irrelevant and stupid, since to fire engineers, the size of the structure is irrelevant. Steel reacts to fire in the same way, no matter what the size.

It fails.

Originally posted by FOXMULDER147


My post was perfectly clear. Here, I'll repeat - If the towers did have extra weight they were not designed to hold - as your theory claims - then by definition they wouldn't have held it.

They were standing fine before the planes hit! Ergo, they were not overloaded with weight.

In any case, your theory is complete nonsense. The "top" sections of the towers only fell a few storeys [the distance of the plane impact damage] onto the "bottom" sections - that distance is nowhere near far enough for the top sections to reach the momentum necessary to completely flatten both towers in 10 seconds.

hmmm according to my handy dandy free fall with quadratic drag calculator large flat steel and concrete slabs free falling through air at sea level would have landed in 9.2 seconds:

hyperphysics.phy-astr.gsu.edu...

Do you have a source that said that the towers collapsed in 10 seconds?

If the towers did have extra weight they were not designed to hold - as your theory claims - then by definition they wouldn't have held it.

DUH. I could have sworn that, by defnition, the towers could not support the weight they had inside them and collapsed? I guess you missed the part where the towers could no longer support the weight inside of them and collapsed.

They were standing fine before the planes hit! Ergo, they were not overloaded with weight.

If you wanna make sure a building collapses after getting hit by airplanes and set on fire you can use, micronukes, the death star lazer, thermite, thermate, bombs, explosives, or extra weight. The buildings could support the extra weight pre airplane and fire but not post airplane and fire.

One of those things could have been pulled off easily without anyone knowing. I'll give you some hints:

1. The death star is not real.
2. Top secret demolition projects in occupied buildings in the middle of new york that are blown in font of 200 million people are not real.
3. eplosives are not silent

that distance is nowhere near far enough for the top sections to reach the momentum necessary to completely flatten both towers in 10 seconds.

Force = Mass * acceleration

you can estimate and do the math. Me and my physics professors
Steven Wilson and Douglas Patterson estimated that 30 floors of falling WTC have 400 times more force than the 110-150 ton 500 mile per hour airplane that hit.

What would the WTC look like if you hit every floor of the WTC with 3 110-150 ton 500 mile per hour airplanes?

A big pile of rubble.




[edit on 25-6-2010 by iamcpc]

[edit on 25-6-2010 by iamcpc]

Originally posted by SphinxMontreal

If you have this massive and very heavy upper part tipping over, nothing will halt it.Gravity, momentum and common sense dictate that it should continue to tip over and drop over the side of the building.

What does your common sense tell you about reaction shearing?

www-math.mit.edu...


Appendix II. Why Didn’t the Upper Part Pivot About Its Base?
Since the top part of the South Tower tilted (Fig. 3a), many people wonder: Why didn’t the
upper part of the tower fall to the side like a tree, pivoting about the center of the critical
floor? (Fig. 3b) To demonstrate why, and thus to justify our previous neglect of tilting, is
an elementary exercise in dynamics.
Assume the center of the floor at the base of the upper part (Fig. 3b) to move for a while
neither laterally nor vertically, i.e., act as a fixed pivot. Equating the kinetic energy of the
upper part rotating as a rigid body about the pivot at its base (Fig. 3c) to the loss of the
gravitational potential energy of that part (which is here simpler than using the Lagrange
equations of motion), we have mg(1 € cos ’)H1=2 = (m=2H1)
R H1
0 (’˙x)2 dx where x is the
vertical coordinate (Fig. 3c). This provides
’˙ =
s
3g
H1
(1 € cos ’); ¨’ =
3g
2H1
sin ’ (4)
11
where ’ = rotation angle of the upper part, H1 = its height, and the superposed dots denote
time derivatives (Fig. 3c).
Considering the dynamic equilibrium of the upper part as a free body, acted upon by
distributed inertia forces and a reaction with horizontal component F at base (Fig. 3d),
one obtains F =
R H1
0 (m=H1) ¨’ cos ’ xdx = 1
2 H1m ¨’ cos ’ = 3
8mg sin 2’. Evidently, the
maximum horizontal reaction during pivoting occurs for ’ = 45Ž, and so
Fmax = 3
8 mg = 3
8 P0 ™ 320 MN (5)
where, for the upper part of South Tower, m ™ 87  106 kg.
Could the combined plastic shear resistance Fp of the columns of one floor (Fig. 3f)
sustain this horizontal reaction? For plastic shear, there would be yield hinges on top and
bottom of each resisting column; Fig. 3e (again, aiming only at an optimistic upper bound
on resistance, we neglect fracture). The moment equilibrium condition for the column as a
free body shows that each column can at most sustain the shear force F1 = 2Mp=h1 where
h1 ™ 2:5 m = effective height of column, and Mp ™ 0:3 MN m = estimated yield bending
moment of one column, if cold. Assuming that the resisting columns are only those at the
sides of the framed tube normal to the axis of rotation, which number about 130, we get
Fp ™ 130F1 ™ 31 MN. So, the maximum horizontal reaction to pivoting would cause the
overload ratio
Fmax=Fp ™ 10:3 (6)
if the resisting columns were cold. Since they are hot, the horizontal reaction to pivoting
would exceed the shear capacity of the heated floor still much more (and far more if fracture
were considered).
Since F is proportional to sin 2’, its value becomes equal to the plastic limit when sin 2’ =
1=10:3. From this we further conclude that the reaction at the base of the upper part of
12
South Tower must have begun shearing the columns plastically already at the inclination
’ ™ 2:8Ž (7)
The pivoting of the upper part must have started by an asymmetric failure of the columns
on one side of building, but already at this very small angle the dynamic horizontal reaction
at the base of the upper part must have reduced the vertical load capacity of the remaining
columns of the critical floor (even if those were not heated). That must have started the
downward motion of the top part of the South Tower, and afterwards its motion must have
become predominantly vertical. Hence, a vertical impact of the upper part onto the lower
part must have been the dominant mechanism.
Finally note that the horizontal reaction Fmax is proportional to the weight of the pivoting
part. Therefore, if a pivoting motion about the center of some lower floor were considered,
Fmax would be still larger.

The analysis of the upper part first having to be stopped by the lower part prior to tipping over makes no sense at all.

That's bacause you don't understand the above engineering. It renders all of your beliefs invalid.

Convince me with some engineering that disputes this, or it's an admission that base your statements on nothing more than your incredulity.



[edit on 25-6-2010 by Joey Canoli]

[edit on 25-6-2010 by Joey Canoli]

Originally posted by iamcpc
I guess you have never dropped a cinderblock on a pop can.

A completely irrelevant analogy. No metaphorical "ciderblock" was dropped on either tower. But, just for fun...

Hold a cinderblock a meter above a pop can and drop it. Sure, it will crush the can. But hold it only a few millimeters above the can, and drop. I don't think the can will be completely crushed.

You're not accounting for the momentum of the falling "top" section.

For your theory to work, the "top" section of the towers would probably have to fall from half a mile above in order to flatten the towers.

That would be the equivalent of dropping a cinderblock on a can. But that's not what happened.

Originally posted by iamcpc
Force = Mass * acceleration

you can estimate and do the math. Me and my physics professors
Steven Wilson and Douglas Patterson estimated that 30 floors of falling WTC have 400 times more force than the 110-150 ton 500 mile per hour airplane that hit.

What would the WTC look like if you hit every floor of the WTC with 3 110-150 ton 500 mile per hour airplanes?

A big pile of rubble.

But, Mr Newton, the "top" section of the towers didn't hit the "lower" section at 500 mph!

Originally posted by FOXMULDER147

Originally posted by iamcpc
Force = Mass * acceleration

A big pile of rubble.

But, Mr Newton, the "top" section of the towers didn't hit the "lower" section at 500 mph!

But it has a lot more mass than a plane.

That's the point of the equation he gave you, but you missed its significance.