# Debunked: WTC: Multi-ton steel sections ejected laterally.

#### drommelsboef

##### Member
If the effect is due to released elastic energy in steel which is about 50 J/kg then if all the elastic strain energy is converted to kinetic energy we simply have

K.E. = 1/2Mv^2, or mass specific kinetic energy = 1/2 v^2 = 50 J/kg

Therefore the maximum ejection velocity of a steel section is 10 m/s and it can reach a maximum distance of about 92m.

#### Jeffrey Orling

##### Senior Member
You wrote 60 mph in a few yards. Chandler's measurements are crap... That's been established beyond a shadow of a doubt.... as is his understanding of building structure. [...]

The facade peeled and toppled. There is no other explanation. You can't explode 40 panels off the tower without them breaking apart ... that is pure hooey.

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#### Hitstirrer

##### Active Member
Chandler's measurements are crap... That's been established beyond a shadow of a doubt....

OK. Now its time for me to ask you produce evidence of your claim that he is in error. If its been 'established beyond a shadow of doubt' then it will take you less than five minutes to produce that work won't it.

#### Mick West

Staff member
If the effect is due to released elastic energy in steel which is about 50 J/kg then if all the elastic strain energy is converted to kinetic energy we simply have

K.E. = 1/2Mv^2, or mass specific kinetic energy = 1/2 v^2 = 50 J/kg

Therefore the maximum ejection velocity of a steel section is 10 m/s and it can reach a maximum distance of about 92m.

But who is suggesting it's due to released elastic energy?

#### Mick West

Staff member
I assume that if such velocities can be proven then you would accept that the 'settled science of toppling' cannot explain that.

Why not? What's the maximum speed that can be achieved by toppling? More importantly, what is the theoretical maximum horizontal distance something can travel under the toppling hypothesis?

I've got some ideas for a demonstration of the mechanism, maybe later.

Oh, and I think this "massive steel beams" is a key way of explaining AE911's lack of actual credibility to people. Why don't they see the flaws in their argument?

#### Oystein

##### Senior Member
If the effect is due to released elastic energy in steel which is about 50 J/kg then if all the elastic strain energy is converted to kinetic energy we simply have

K.E. = 1/2Mv^2, or mass specific kinetic energy = 1/2 v^2 = 50 J/kg

Therefore the maximum ejection velocity of a steel section is 10 m/s and it can reach a maximum distance of about 92m.
Can someone confirm this for me - that steel can store a max. elastic strain energy of 50 J/kg? I am slightly surprised that strain enegy is proportional to mass (and thus to volume), not depth or area or something <3D, but that may well be merely my non-expert intuition failing me here.

But who is suggesting it's due to released elastic energy?
"Bouncing" is elastic impact, isn't it? Your experiment doesn't permanently deform any of the involved steel parts, so you basically have fully elastic bounces, but I very much doubt that this would scale to multi-ton panels falling hundreds of feet - the reason being the limit strain steel can take. With energy lost to plastic deformation upon impact, the bounce will be less.

#### Oystein

##### Senior Member
A few months ago, I posted a detailed calculation to estimate the mass of high explosives needed to propel an object (a piece of steel) to 60 mph - a velocity claimed by Dr. Griscom, a truther and physics professor. First the link to that post:

I figured that it would take significantly more than 10 kg of explosives for each 1000 kg of steel to reach thiose 60 mph.

And here copy&paste the calculation:

Let's apply the laws of Conversation of Momentum and Conversation of Energy to the problem: How much explosives does it take to throw one ton (1000 kg) at 60 mph = 27 m/s?

When a massive object (let's denote its mass as m(o)) is propelled by a chemical propellant (mass = m(p)), such as an explosive substance, that's attached to it, two things happen at the same time:
1. Object o is accelerated to some velocity v(o) in one direction.
2. Reaction products p of the propellant are accelerated to some velocity v(p) in the opposite direction.
(For nit-pickers: The products move in several directions, and velocity of individual molecules may differ greatly; it is actually the center of mass of the products cloud that matters here. We'll come back to this later. Ignoring this velocity distribution is actually a "explosive-friendly" simplification. Another nitpick: If the propellant acts off-center on the object, it will impart angular momentum. I'll ignore that here completely, as it makes calculations more cumbersome; it can be shown though that IF that makes a difference, it makes Mr. Griscom's problems even greater)
Now, since the system of object+propellant before the "explosion" was at rest, it had a linear, lateral momentum of zero. After the explosion, the system momentum must still be zero to satisfy the law of Conservation of Momentum (CoM).
That law requires in this situation that
(1) m(o)*v(o) = -m(p)*v(p).
Lets play with some numbers to see what that means practically: Let's say we have a steel piece of 1000 kg, and an explosive charge of 1 kg. After the explosion, the object moves at 60 mph (I am quoting your number) = 27 m/s (I prefer SI units). Let's plug this into equation (1):
(2) 1000 kg * 27 m/s = 1 kg * v(p)
and solve for velocity of the explosive's products:
(3) v(p) = 27,000 m/s
That's about 90x the speed of sound. Quite unreal.
Similarly, a charge of 10 kg would have to result in a gas velocity of 2,700 m/s.

Now we have to look at the other law, Conversation of Energy (CoE)! All the energy to accelerate both the object and the propellants comes from the chemical energy of the explosive - let's denote that as E(chem). In the explosion event, this energy is transformed into several components:
- Kinetic energy of the object - E(kin, o)
- Kinetic energy of the explosive products - E(kin, p)
- Heat
- Deformation of steel
- Sound, seismic, ... energies
The latter three are difficult to evaluate, but must be >0 (again, by ignoring that term or assuming it to be insignificantly low, we make things easier on Mr. Griscom; it's a "explosive-friendly" simplification). Let us denote them jointly as E(rem) (rem="remaining"), then we can write down the applicable CoE equation as
(4) E(chem) = E(kin, o) + E (kin, p) + E(rem) = 1/2 m(o) * v(o)^2 + 1/2 m(p) * v(p)^2 + E(rem)
Let's plug in numbers for the first example (1 kg of explosives) as we derived them from CoM considerations (3):
(5) E(chem) = 1/2 * 1000 kg * (27 m/s)^2 + 1/2 * 1 kg * (27,000 m/s)^2 + E(rem) = 364,864,500 J + E(rem)
So 1 kg of the explosive would have to have more than 364 MJ energy. This is impossible. There exists no chemical substance that even comes close. Most high explosives, and also thermite, have a specific energy in the vicinity of 4 MJ/kg.
Let's try the same with 10 kg of explosives:
(6) E(chem) = 1/2 * 1000 kg * (27 m/s)^2 + 1/2 * 10 kg * (2,700 m/s)^2 + E(rem) = 36.814,5 MJ + E(rem)
Now the result approaches the realistically possible: The result means that the explosive would have to release a specific energy of about 3,7 MJ/kg, and would explode at 2,700 m/s (9x speed of sound in air). Both numbers are realistic for efficient high explosives (albeit still a bit out-of-range for thermitic materials).
In practice, it gets worse than that: As I remarked earlier, the explosive's products would not all shoot out in the same direction at the same speed; some would shoot faster, some slower; some exactly opposite to the movement of the steel object, but much at an angle. These effects all tend to increase the required kinetic energy of the products. Also, there will of course be some loss to heat, deformation work etc. - it only works out if the explosive does relatively little damage to the steel, and produces no heat (little spare energy to melt steel, for example, and form iron-rich spheres ).

In short: To accelerate an object to 60 mph, you need significantly more than 10 kg of high explosives (whether conventional or "thermitic" doesn't make much difference) per 1000 kg of object mass. The perimeter columns high on the impact-and-fire floors weighed more than 2 tons per floor (more in the lower floors, as plate thickness increased for higher loads). You probably know that these columns came in pieces of about 11 m (36 ft), so we are getting close to 7 tons per perimeter column. A perimeter panel, consisting of 3 adjacent columns, welded together with spandrel plates, weighed close to 30 tons. To propel one column to 60 mph, you need more than 100 kg of high explosive. For a full panel (and much of what was found in the WFC winter garden was full panels) you'd need in excess of 400 kg of high explosives. If you want to do that with some hypothetical kind of "quiet" explosives, you'd need yet again much much more (factor: 10+) to avoid the 9x speed of sound problem.

A detonation of 10 kg of high explosives makes a HUGE imprint on the sound track. You certainly have listened to videos of actual explosive demolitions? What you hear there are mostly charges of only some ounces of explosives. They are incredibly, AWESOMELY loud every time, and are far and away the most outstanding feature of every such video.

Propelling steel ejecta to 60 mph would require MUCH MUCH larger explosive charges than anything ever employed at any CD, and it would be almost entirely a waste of energy, as there is no reason to "eject" anything at all. You want to put as close to 100% of the chemical energy into material deformation, 0% to kinetic energy.
Content from External Source
(Important note: I overestimated the mass of the wall panels - instead of 30 tons, it should be about 6-7.5 tons for panels above the 78th floor., That would reduce the 400 kg estimate to 80-100 kg)

#### econ41

##### Senior Member
Even if sufficient energy can be produced how much is wasted?

How much of the energy from the explosion acts on the area of the projected beam exposed to the blast?

How is the blast focussed to ensure a sufficient portion of the available energy does impact on the beam?

#### Hitstirrer

##### Active Member
I assume that @Jeffrey Orling has been unable to justify his wild accusation that Chandlers velocity calculations were, in his words, 'crap'. Verification of Chandlers result has been confirmed by Dr Griscom and appears to have been accepted.

Much effort has been expended by @drommelsboef and @Oystein to demonstrate that such velocities and distances ejected are impossible, absent huge explosions and noise. As if that proves that what has been observed, recorded, and measured, didn't happen because their calculations say so.

@Mick West says, - " What's the maximum speed that can be achieved by toppling? More importantly, what is the theoretical maximum horizontal distance something can travel under the toppling hypothesis?". A valid question.

If experimentaion or calculations shows that a simple toppling under gravity - possibly enhanced by a combination of elastic steel and 'bouncing' effects - cannot enable large steel sections to achieve the velocities and lateral distances as calculated and observed, then some other force input needs to be considered.

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#### econ41

##### Senior Member
I assume that @Jeffrey Orling has been unable to justify his wild accusation that Chandlers velocity calculations were, in his words, 'crap'. Verification of Chandlers result has been confirmed by Dr Griscom and appears to have been accepted.
Get your burden of proof round the right way. You are claiming Chandler as an authority for that specific measurement. Your burden of proof to prove the velocity. And - if you want to use Chandler as an authority - you have to prove that he made that measurement and that his work is valid.

The related issue of context is that most of us here - including Jeffrey O - are aware of multiple examples of Chandler's range of work which are untruthful and show his incompetence OR dishonesty. THEREFORE if you want to claim he is right on the one specific issue you face a greater difficulty persuading us.

And you still need to disprove "bowling"/toppling.

#### Hama Neggs

##### Senior Member.
Here's video I took of the girder bounce experiment.
Seems like it would have lot to do with the 'springiness' of the beam and impacted body.

#### Hitstirrer

##### Active Member
Get your burden of proof round the right way. You are claiming Chandler as an authority for that specific measurement. Your burden of proof to prove the velocity. And - if you want to use Chandler as an authority - you have to prove that he made that measurement and that his work is valid.

The related issue of context is that most of us here - including Jeffrey O - are aware of multiple examples of Chandler's range of work which are untruthful and show his incompetence OR dishonesty. THEREFORE if you want to claim he is right on the one specific issue you face a greater difficulty persuading us.

And you still need to disprove "bowling"/toppling.

Wrong in so many ways. I merely answered a request to provide some evidence to support a comment I made. I made no claim that Chandler was an authority on that subject. Having supplied that evidence as requested I was met by an intemperate bare assertion that Chandlers' work was 'crap'. ( Has the politeness policy been abandoned in here in my absence )

Asking him to back that wild claim up was quite valid, and still is, as he has so far failed to do that. Your own input is an attempt to allow him to evade that responsibility. As it happens, @Oystein provided confirmation of Chandlers calculations by mentioning that Dr Griscom also reached the same conclusion, so I look forward to @Jeffrey Orling 's own input to refute both of their calculations. I dont have to prove that their work is valid. Others have to show where they are in error.

You then reveal your real agenda here by alleging prior problems over Chandler's work. As if that in any way invalidates these particular calculations. Someone can be wrong multiple times but that doesnt automatically mean that another calculation is also wrong. Critical thinking skills fail there. Get his data checked. And if its wrong I would be the first to accept that. On the other hand, if he ( and Griscom ) are right then you need to face up to the implications.

And I have no need to disprove anything here. We need much more information first. And @Mick West had some valid questions that need to be examined first.

#### Mick West

Staff member
Has anyone ever suggested a mechanism where an explosion might hurl a 20 ton wall section 250 feet, but not hurl smaller debris tens of miles?

#### Spectrar Ghost

##### Senior Member.
Air resistance. Though you're certainly right that we could expect to see progressively finer debris the further away from the explosion you went.

#### Hitstirrer

##### Active Member
Has anyone ever suggested a mechanism where an explosion might hurl a 20 ton wall section 250 feet, but not hurl smaller debris tens of miles?

Isn't part of the CD theory that the concrete was reduced to talcum particle size powdered dust in the explosions that ejected steel. And wasn't that what we saw. Dust clouds. But you are right of course. There had to be some ejecta that was larger than talcum powder and smaller than steel sections. Possibly too small to be seen and measured on the videos from a mile away though. Certainly much rubble as you suggest was seen spread all over NY that day.

#### econ41

##### Senior Member
Has anyone ever suggested a mechanism where an explosion might hurl a 20 ton wall section 250 feet, but not hurl smaller debris tens of miles?
I've never quantified it myself nor seen it validly quantified by others. Hence my recent comments responding to Oystein's post.

The usual presumption and inference of truther claims is that explosives can project large steel beams.

I have commented many times on several forums that it is well nigh impossible to project heavy steel beams using explosives in the WTC setting. The big problem is that there is nothing to focus, contain and concentrate the blast to allow it time to accelerate a large beam.

The problem is worse with HE than it is with "lower" explosives such as ANFO or black powder. ANFO used in quarrying often will project a large rock to a distance BUT it starts in a mass of dirt lifted by the ANFO and momentum allows the rock to continue. The initial "launch" using the mass of earth/rock/debris as a focussing container till the momentum is achieved.

A gun barrel is the obvious focussing container and works with black powder or other propellants. HE in a gun barrel would shatter the barrel BEFORE the momentum transfer could be achieved.

There is no such "containment mechanism" in the WTC scenarios. And postulating that one was set-up merely adds additional layers of improbable complexity to CD claims. When both the bowling and the bouncing/skittering mechanisms achieve the effect of apparent throwing to the distances which occurred.

And the "rock in a mass of dirt" goes against your "smaller debris goes miles". Yes metal splinters do go for great distances from HE cutting of steel. When I did my Military Engineering demolition course the demo range was under one of the approach paths for Sydney Airport. From memory at the 7000feet "step" in the descent pattern. That approach was closed to air traffic whilst steel cutting was being conducted.

"Splinters" from HE cutting of steel can go to distance but dust and dirt from LE quarry blasting do not go as far as those occasional entrained rocks. Air resistance versus moving weight being the limitation.

#### Mick West

Staff member
Air resistance. Though you're certainly right that we could expect to see progressively finer debris the further away from the explosion you went.

I'm talking about things like nuts and bolts, or even chunks of concrete, rebar, the more solid contents of the office, like statues, etc. Air resistance is not going to do much to that over a mile or so.

Isn't part of the CD theory that the concrete was reduced to talcum particle size powdered dust in the explosions that ejected steel. And wasn't that what we saw. Dust clouds. But you are right of course. There had to be some ejecta that was larger than talcum powder and smaller than steel sections. Possibly too small to be seen and measured on the videos from a mile away though. Certainly much rubble as you suggest was seen spread all over NY that day.

Lots of dust was, but let's do some ballpark math here. An explosion moves things by pushing them with expanding gases, the force that those expanding gasses are going to impart is proportional to the surface area. The acceleration is inversely proportional to the mass. Mass is proportional to the cube of a linear dimension. Cross section is proportional to the square.

So let's take two similar shaped objects, like a wall section, and a metal splice plate, or a slab of marble. one is (say, just ballparking here) 30 feet long, and the other is 3 feet long. So the large object is 10 times as long, so it has 100x as much cross sectional area, so gets 100x as much force from the explosion.

However it's got 1,000x the mass. So if it has 100x the force, but 1000x the mass, then acceleration is going to be 1/10th the amount for the larger object, or 10x the amount for the smaller.

So if the "explosion" is shooting a 30 foot steel section 200 feet, it should be shooting 3 feet steel sections 2,000 feet.

And it should be shooting 3" pieces of steel 24,000 feet (4.5 miles)

Backing up a little, that 30 foot long section, travelled about 250 feet, let's say it fell 800 feet, that's about 7 seconds. So it also travelled 250 feet in 7 seconds, hence the ejection speed was about 24 mph.

So, if an "explosion" can accelerate a 30 foot long section to 24 mph, it will accelerate a 3 foot section to 240 mph, and a 3" section to 2,880 mph.

And there must have been many thousands, if not millions of pieces in the WTC that were under 3", and hence many of these pieces would have been accelerated (initially) to speeds in excess of 3,000 mph. Hence if there was such an explosion then the surrounding buildings would be perforated like swiss cheese on both sides, as these lumps of steel ripped through them literally like cannonballs.

But we didn't see anything like this. We didn't find thousands of 3" or smaller sized pieces of debris five miles from the site, we didn't hear a series of incredibly loud explosions (as if a 3" piece of steel is going faster than the speed of sound, then the air is going MUCH faster, so a loud bang is an inevitable consequence of this "explosive ejections of large steel sections" theory), there's no evidence such an explosion took place, and very compelling evidence (you might even consider it 100% proof) that there was no such explosion.

At yet for years this has been a centerpiece of AE911's hypothesis.

(notice they up things to 600 feet, and 60 mph, which of course just makes things far worse).

Anyone who has looked at this for long enough should know that AE911's list of "key evidence" is specious, meaningless, or just flat wrong. But they are supposed to be engineers (or at least architects), and simple math like F = ma, and "time to fall" should not be too complicated for them, at least for some of them.

So why have they got it wrong for so long? Why allow this nonsense to stand on the front page? What does this say about the membership, and the leadership, of AE911?

It says that they don't really understand the science.

They are not doing math, they are not doing engineering, they are just pointing at things that look amazing to them, things that they don't understand. The building fell rapidly, there was a lot of dust, some adjacent buildings were struck by falling debris hundreds of feet away.

"How is this possible?", they ask. And they ask because they don't know. Because they can't, or they won't, just do the math.

#### Mick West

Staff member
And just to be clear how deeply AE911 has bought into this theory, have a look at this video (which is linked from their "Key Evidence" list)

#### econ41

##### Senior Member
I'm talking about things like nuts and bolts, or even chunks of concrete, rebar, the more solid contents of the office, like statues, etc. Air resistance is not going to do much to that over a mile or so.
Similar thinking to mine Mick - at the size scale of nuts and bolts where my experience identifies "splinters" or "shards"

Lots of dust was, but let's do some ballpark math here....
My own version of "ball park maths" tries to reconcile the expanding sphere of gas from an explosion applying pressure to the face of the beam oriented towards the expanding gas.

The energy of the expanding gas - unconstrained - will be uniformly distributed around the sphere. And the face of the beam taking the pressure will be a very small portion of that sphere. Therefore a very small portion of the energy getting applied to accelerating the beam.

Anyone who has looked at this for long enough should know that AE911's list of "key evidence" is specious, meaningless, or just flat wrong. But they are supposed to be engineers (or at least architects), and simple math like F = ma, and "time to fall" should not be too complicated for them, at least for some of them.

So why have they got it wrong for so long? Why allow this nonsense to stand on the front page? What does this say about the membership, and the leadership, of AE911?
Agreed.

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#### Mick West

Staff member
You can see a practical example here:

The heavy rear loader only goes a few feet, but other pieces are shot hundreds of feet in the air, and there must be smaller pieces that are not visible that go further:

##### Senior Member
they don't have to do the math, because in the words of their chairman, Dan Barnum

They "knew"

Dan “knew” at the outset that something was fishy about 9/11, because both of the buildings collapsed suddenly, and in the same manner.

#### BombDr

##### Senior Member.
Has anyone ever suggested a mechanism where an explosion might hurl a 20 ton wall section 250 feet, but not hurl smaller debris tens of miles?
Good point Mick: The safety distance in the UK for cutting metal on the demolition range is 1000m.

Why were the surrounded people, buildings and vehicles near to 'Ground Zero' not peppered with fragmentation from these steel-cutting charges?

#### OneWhiteEye

##### Senior Member
A few months ago, I posted a detailed calculation...
The response(s) to this in the linked thread - a train wreck.

##### Senior Member
Why would the controlled demolition start at the top of the buildings anyway

Isn't it more usual to start at the bottom, making better use of gravity etc

#### OneWhiteEye

##### Senior Member
Why would the controlled demolition start at the top of the buildings anyway

Isn't it more usual to start at the bottom, making better use of gravity etc
Might attract some unwanted attention.

#### econ41

##### Senior Member
Why would the controlled demolition start at the top of the buildings anyway

Isn't it more usual to start at the bottom, making better use of gravity etc
Yes - true.

In addition that's one of the concepts we get wrong - both "sides".

If there was demolition assistance to the collapses there is no reason it needed to be "controlled" in the normal meaning applied to such activities. i.e. preventing collateral damage OR limiting the spread of debris.

#### Hitstirrer

##### Active Member
Why were the surrounded people, buildings and vehicles near to 'Ground Zero' not peppered with fragmentation from these steel-cutting charges?

They were. But not from C4 or similar. In fact the whole NY area was. Billions of iron rich microspheres as discussed eleswhere.

#### BombDr

##### Senior Member.
They were. But not from C4 or similar. In fact the whole NY area was. Billions of iron rich microspheres as discussed eleswhere.
I'm confused now. The 'explosions' were powerful enough to 'eject' large frame steelworks away from the building weighing several tons, but there was no fragmentation of any sort that weighed several grams, yet micro-particles of another sort were liberally distributed?

How does that demolition emit some metal debris that is heavy, yet retain the smaller, fragmentation sized parts?

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#### Hitstirrer

##### Active Member
How does that demolition emit some metal debris that is heavy, yet retain the smaller, fragmentation sized parts?

But you don't know that such fragments were retained. I would suspect that the area around was liberally sprinkled with smaller fragments. Very tiny particles, such as iron rich microspheres, would blow outwards and upwards. Larger particles would blow outwards and downwards. But you know this. Its physics. So why do you suggest that they would be retained? The videos display that quite well after all.

#### Mick West

Staff member
They were. But not from C4 or similar. In fact the whole NY area was. Billions of iron rich microspheres as discussed eleswhere.

The distribution of micro-sized particles in determined almost entirely by air movement. That is not the topic here.

We are talking about the "ejection" of multi-ton steel sections (which ended up over 200 feet horizontally from where they started, falling maybe 800 feet), and what might have caused that.

AE911 suggest it was caused by explosions, but the lack of smaller sections traveling much faster and much longer distances proves that is could not have been.

If you want to disagree, then please point out the error in the physics discussed above.

#### Keith Beachy

##### Senior Member
...
But the question remains. What force caused the massive sections to break free on three sides only and then 'topple' sideways with huge acceleration and at a measured velocity far in excess of that possible by a gravitational 'topple' about a fixed point. ...
What force, what energy was there? E=mgh was there, sitting, and when the top failed, it was released over the collapse, ejecting material as would happen due to collisions.

The energy in each tower released was equal in energy to 137 2,000 pound bombs; in each tower. I ask myself, is 576,210,000,000 joules enough to do what we saw; and the answer is yes. Simple physics, no fancy presentation of nonsense by fake experts; simple physics, E=mgh, the energy releases on 911 due to massive fires in a building with failed fire systems, and destroyed insulation due to aircraft impacts.

Simple physics, E=mgh, a number calculated with simple math. More than enough energy is available, and proved by what was seen on 911.

How big a silent explosives was used in 911 truth's inside job scenario? What is the size of the silent explosives needed for the fantasy version of ejections, where bad guys loaded fireproof silent explosives in the WTC without detection.

Now what amount of energy is required to eject the material you think can't be ejected in a gravity collapse. How many joules do we need; do you have a number? The WTC has 576,210,000,000 joules from each tower, which destroyed the WTC, gravity did it, fires started it. Ironically, in the controlled demolitions, the majority of energy used to destroy buildings is E=mgh released. Controlled demolitions are gravity collapses, where the energy stored in the building is used to destroy the building, and small amounts of explosives are used to start the collapse.

#### BombDr

##### Senior Member.
Larger particles would blow outwards and downwards. But you know this. Its physics. So why do you suggest that they would be retained? The videos display that quite well after all.

If you cut metal with explosives, it will primary frag like this:

These will be flying through the air at around 8000 m/sec, which is why we have a safety distance of 1000m when cutting metal on a demolition range.

These shards, when they strike vehicles or buildings leave strike marks like these:
Or this:

Or this:

Is there any evidence that vehicles, people or building have been struck by primary frag, from cutting charges on metal, and if not, why has these particular claimed explosions uniquely had either very large or microscopically small fragmentation, and none in between?

#### Mick West

Staff member
I don't think energy discussion are really relevant here. The problem is more about (relatively) simple physics: force, mass, area, length, velocity, height, distance, friction.

Adding energy to the discussion is unnecessary, and potentially confusing. And the question "was there enough energy to ...." is a different topic.

#### Spectrar Ghost

##### Senior Member.
What is the justification for claiming these sections broke free on only three sides?

#### Mick West

Staff member
Is there any evidence that vehicles, people or building have been struck by primary frag, from cutting charges on metal, and if not, why has these particular claimed explosions uniquely had either very large or microscopically small fragmentation, and none in between?

I suspect the answer to this lack of frag is that the "explosions" were a series of carefully placed thin layers of a novel top secret form of nano-thermite that just burnt very rapidly, but not too rapidly.

But of course this explanation would be unacceptable here, as it does not explain "Multi-ton steel sections ejected laterally."

#### Mick West

Staff member
What is the justification for claiming these sections broke free on only three sides?

And why is that even relevant? Large sections fell, and travelled 200 feet. That they did it somewhat unevenly speaks only to some asymmetry in the mechanism, it does not disqualify either hypothesized mechanism. The lack of inch-sized debris miles away disqualifies the explosion hypothesis.

#### BombDr

##### Senior Member.
I suspect the answer to this lack of frag is that the "explosions" were a series of carefully placed thin layers of a novel top secret form of nano-thermite that just burnt very rapidly, but not too rapidly.

Well that was where my line of enquiry was going. If it was thermite, what caused the larger columns to seemingly 'eject' from the buildings, and if it was cutting charges, why the amazingly discriminate sizes of the frag...?

They cannot have both arguments, and claim they both 'fell in its own footprint', whilst simultaneously 'ejected' massive columns hundreds of feet away.

#### Hitstirrer

##### Active Member
What is the justification for claiming these sections broke free on only three sides?

I think that came about as a result tof the 'toppling' theory to explain how large sections manage to move sideways rather than downwards under gravity. Its imagined that they break away laterally, and at the top, but the base remains fixed to provide a hinge. The then unstable section topples over to one side around that hinge to enable large sections to be observed travelling sideways and fall many feet away from the base. Without that hinge the toppling theory becomes untenable.

#### Spectrar Ghost

##### Senior Member.
If I stand a two by four upright and let it fall over, it topples because its base is bound gravitationally to the ground. A physical connection is not required.

#### Mick West

Staff member
I think that came about as a result tof the 'toppling' theory to explain how large sections manage to move sideways rather than downwards under gravity. Its imagined that they break away laterally, and at the top, but the base remains fixed to provide a hinge. The then unstable section topples over to one side around that hinge to enable large sections to be observed travelling sideways and fall many feet away from the base. Without that hinge the toppling theory becomes untenable.

I don't think anyone has suggested the bottom of the building as a hinge. There would be multiple pivot points as collapse progressed. The hypothesis being that interior floors were stripped away, and the walls just peeled away at that point.

The red dots here indicate the pivot points of different sections.

Of course it was not a simple process, the wall mostly cam apart at the joins, but then there were also some very big sections that pivoted away.