So still think the towers were brought down without bombs?

[xrayzebra]

^^you lost dan after your first sentence. He has problems
dressing himself, much less addressing anything with more than
two words in the sentence. He just learned how to cut and paste
a few years ago. And how to google.

[ChumpDumper]

namely the rapid and symmetrical and complete (no tall-standing central core) collapses.

Dan, don't you remember posting that 40 floors worth of central column was left standing for a time after the initial collapse?

Is it difficult to keep track of which conspiracy contradicts the other?

[RandomGuy]

If I drop a bowling ball and a 1/2 inch ball bearing from 10 feet, which will hit the ground first?

Dan probably won't address this either, so let's examine THIS too.

They hit the ground at the same time.

Now, imagine you superglue that ball bearing to the WTC roof, and at the same time, suspend the bowling ball from a helicopter on a rope so that the bowling ball it at the EXACT same level as the ball bearing.

Start the collapse.

The ballbearing/top section tilts over and falls through the air, just as in the picture.

At the same time you drop the bowling ball.

The ball bearing will hit the ground slightly after the bowling ball, because the first instant or two had some resistance as it was toppling over, but within a minute fraction of a second, in other words, effectively at the same time.

Try the experiment again.

This time, drop the ball THROUGH the building at the same time the ball bearing starts to move.

IF dan's thesis is correct, the bowling ball will hit the ground AT THE SAME TIME, because he says that the building is being collapsed at a simulated free fall speed because of explosions.

SO at everypoint in that fall, the bowling ball, falling and following the collapsing wavefront, should be at the same level.

The wavefront of the collapse and the FIRST part of the falling section should be at the same level AT ALL TIMES.

Is this what the pictures show?

[RandomGuy]

At this point, it is worth noting that I am an accountant with a liberal arts background. I have had only two semesters of physics in the last 20 years.

THAT is how little expertise it takes to see through the "911 Physics" bull .

[ChumpDumper]

So where exactly were the core charges placed?

[ChumpDumper]

And why would they cause the top of the building to come down at an angle initially?

[Nbadan]

Only about 10% of the concrete was really unaccounted for, if memory serves. Erg, can't remember where I saw it.

So what happened to the concrete?

[Nbadan]

For whatever it's worth, here's the link that dan forgot in his failure to attribute his conclusions to their real source: Physics 911

One of many sources, but you forgot that part.

[Nbadan]

Physics 911 is a joke. My response YET AGAIN, because I am still waiting on dan to address anything in it:
PE = m x g x h

Consider the mass of just the top floor of the building.

PE= m *9.8*413= 4073m

Mass is, by definition, simply a measurement of how much force a given amount of material will exert AT REST on an object that is resisting gravity.

SOOOO

The top floor would hit the ground with the same force as a 4073 story building, if that fall was unimpeded.

Now let's consider the fall of the top 30 stories.

They fell through the 3-5 floors of damaged sections and impacted the building below with some amount of force.

Let's call the distance accelerated as 3 floors and be generous. This is 11 meters.

Acceration of an object for 11 meters at 70% of gravity(dan's figure), would yeild an ending velocity of:

v^2= 2ad=2*9.8*.7*11=150=v^2, find the square root of 150, and bada bing, you get 12 meters per second

Subs ute this into the kinetic energy equation:
ke= 150*.5*m=ke=75m

This means the 30 foot section impacts the undamaged portion with the kinetic energy of SEVENTY FIVE TIMES ITS MASS.

Think about this for a moment.

The lower section of the building is designed to hold that 30 stories stationary plus a safety margin of 10 or 20%. So the maximum force that the underlying structure could apply to that falling section is 1.2 times its mass.

Further:
That falling section having as much kinetic energy as 75 times its mass means that it is effectively applying the same amount of force at the impact point that a 2270 story building would. if you held it stationary. (simple math: 30*75)
For the statement "the building would not have collapsed without explosives" implies that the building could have been TWENTY TWO TIMES TALLER THAN IT ACTUALLY WAS without collapsing.

STILL FURTHER

Your calculations seem to imply that the building structure below could absorb 30% of the falling energy.

IN JUST THE FIRST 11 METERS OF A 400 METER COLLAPSE THERE IS 62 TIMES THE AMOUNT OF FORCE REQUIRED TO COLLAPSE THE BUILDING.

Your assumption of about 1/3 the energy used to collapse the building is about 20 times what is reasonable. (1/62*20= 1/3) (more actually, if you consider the further distance and mass)

What happens, then when MORE mass is added AND accelerated?

Even if half the mass falls away or off to the side, there is still FAR more force and energy than would be needed to collapse the building WITHOUT ANY EXPLOSIVES.

Your assuming that the top of the building came down in one huge load-bearing piece, which every video of the collapse shows not to be the case. The top part of the building crumbles into millions of little pieces many of which fall off the side as it hits the lower part of the towers that are still standing, other which are unexplainably shot hundreds of feet away from the footprints of both towers. This all requires huge amounts of energy, neither of which your calculations have accounted for, RG.

[RandomGuy]

300C is all it takes for steel to lose 20% of its loadbearing capacity.

1100C melts steel.

Does a steel column have to be melted to sag from load?

No.

If a good chunk of the damaged sections columns were taken out, say 12 out of 47, then the remaining bits would have to take up the extra load.

Keep things simple here, and take one divided by 47 is .0212, meaning each column bears 2.12 percent of the total undamaged load that the columns were designed for.

Now take out 12 of those columns. one divided by 35 is .0285, or 2.85% of the load they were designed for.

Doesn't sound like much of a difference does it?

BUT

Divide 2.85 by 2.12 and you get 1.34

Taking out 25% of the columns (12/47) means that the remaining columns must bear 34% more weight EACH.

So if all it takes is 300C heat to cause a 20% loss, and each column is bearing around 34% more weight, let's see how that works out when you plug some numbers into it.

Assume the column is designed to hold, say 140 pounds, and only holds 100.

Now sap 20% of the strength out of the column. 140-28= 112.
Now add 34% of the load to the column, or another 34 pounds.

The column is holding 134 pounds, but it can only hold 112 because it has lost load bearing capacity.

These are arbitrary numbers, but you see the principle.

If you put a greater load on something and at the same time start reducing that thing's ability to bear loads, it doesn't take much for the load to overwhelm the resistance.

In the above example, the column would have to be designed to bear 168% of the load it currently does to not collapse.

IN ADDITION

Before the collapse, the steel will become somewhat plastic, meaning it will start to sag, you will see this when the steel starts getting close to the point at which the loads it bears exceeds its capacity.

This is exactly what we started to see in the WTC. The inner columns started to sag, and this started to bow the floor inwards, as the floor bows inwards, it pulled on the outer face of the building that wasn't damaged by the plane impacts. The floor/wall connections here serve to help the building hold up a bit longer as the load is transferred to the outer skin somewhat.

[RandomGuy]

Your assuming that the top of the building came down in one huge load-bearing piece, which every video of the collapse shows not to be the case. The top part of the building crumbles into millions of little pieces many of which fall off the side as it hits the lower part of the towers that are still standing, other which are unexplainably shot hundreds of feet away from the footprints of both towers. This all requires huge amounts of energy, neither of which your calculations have accounted for, RG.

Ok then.

Let's assume it came down in 100 peices.

Does that alter the amount of kinetic energy?

[ChumpDumper]

This all requires huge amounts of energy, neither of which your calculations have accounted for, RG.

the same amount of force at the impact point that a 2270 story building would.

Maybe it's me, but that seems like alot of energy.

[Nbadan]

300C is all it takes for steel to lose 20% of its loadbearing capacity.

1100C melts steel.

Does a steel column have to be melted to sag from load?

No.

If a good chunk of the damaged sections columns were taken out, say 12 out of 47, then the remaining bits would have to take up the extra load.

Keep things simple here, and take one divided by 47 is .0212, meaning each column bears 2.12 percent of the total undamaged load that the columns were designed for.

Now take out 12 of those columns. one divided by 35 is .0285, or 2.85% of the load they were designed for.

Doesn't sound like much of a difference does it?

BUT

Divide 2.85 by 2.12 and you get 1.34

Taking out 25% of the columns (12/47) means that the remaining columns must bear 34% more weight EACH.

So if all it takes is 300C heat to cause a 20% loss, and each column is bearing around 34% more weight, let's see how that works out when you plug some numbers into it.

Assume the column is designed to hold, say 140 pounds, and only holds 100.

Now sap 20% of the strength out of the column. 140-28= 112.
Now add 34% of the load to the column, or another 34 pounds.

The column is holding 134 pounds, but it can only hold 112 because it has lost load bearing capacity.

These are arbitrary numbers, but you see the principle.

If you put a greater load on something and at the same time start reducing that thing's ability to bear loads, it doesn't take much for the load to overwhelm the resistance.

In the above example, the column would have to be designed to bear 168% of the load it currently does to not collapse.

IN ADDITION

Before the collapse, the steel will become somewhat plastic, meaning it will start to sag, you will see this when the steel starts getting close to the point at which the loads it bears exceeds its capacity.

This is exactly what we started to see in the WTC. The inner columns started to sag, and this started to bow the floor inwards, as the floor bows inwards, it pulled on the outer face of the building that wasn't damaged by the plane impacts. The floor/wall connections here serve to help the building hold up a bit longer as the load is transferred to the outer skin somewhat.

So tell me RG, how did each floor of all three towers meet the necessary temperature for simulaneous truss collapse? Otherwise, explain to me how the buildings all fell at free fall speed again?

[ChumpDumper]

Otherwise, explain to me how the buildings all fell at free fall speed again?

They didn't.

[RandomGuy]

Your assuming that the top of the building came down in one huge load-bearing piece, which every video of the collapse shows not to be the case. The top part of the building crumbles into millions of little pieces many of which fall off the side as it hits the lower part of the towers that are still standing, other which are unexplainably shot hundreds of feet away from the footprints of both towers. This all requires huge amounts of energy, neither of which your calculations have accounted for, RG.

Further, let's assume that half the mass falls off to the side.

Half of 75 is what? 37.5

This means that the half that did impact hit with the force of only 37.5 times the mass of the stationary whole.

37 is still a abit more than 1

, let's go for it and assume that 90% of the mass fell off to the side.

75*.1=7.5

Last I checked, 7.5 still is bigger than 1.2.

Now let's examine that "shot hundreds of feet" bit.

Let's assume hundreds of feet =300 feet.

Lets assume no "gliding" or air resistance.

Let's use your figure of 10 seconds for the collapse.

300/10=30 feet per second. (assuming no additional acceleration after initial force)

That is 20 miles per hour.

Hmmm. That doesn't meet my definition of "shot".

[RandomGuy]

So tell me RG, how did each floor of all three towers meet the necessary temperature for simulaneous truss collapse? Otherwise, explain to me how the buildings all fell at free fall speed again?

The buildings didn't fall at free fall speeds, the pictures clearly show they didn't.

If I drop a bowling ball and a 1/2 inch ball bearing from 10 feet, which will hit the ground first?

Dan probably won't address this either, so let's examine THIS too.

They hit the ground at the same time.

Now, imagine you superglue that ball bearing to the WTC roof, and at the same time, suspend the bowling ball from a helicopter on a rope so that the bowling ball it at the EXACT same level as the ball bearing.

Start the collapse.

The ballbearing/top section tilts over and falls through the air, just as in the picture.

At the same time you drop the bowling ball.

The ball bearing will hit the ground slightly after the bowling ball, because the first instant or two had some resistance as it was toppling over, but within a minute fraction of a second, in other words, effectively at the same time.

Try the experiment again.

This time, drop the ball THROUGH the building at the same time the ball bearing starts to move.

IF dan's thesis is correct, the bowling ball will hit the ground AT THE SAME TIME, because he says that the building is being collapsed at a simulated free fall speed because of explosions.

SO at everypoint in that fall, the bowling ball, falling and following the collapsing wavefront, should be at the same level.

The wavefront of the collapse and the FIRST part of the falling section should be at the same level AT ALL TIMES.

Is this what the pictures show?

[RandomGuy]

For whatever it's worth, here's the link that dan forgot in his failure to attribute his conclusions to their real source: Physics 911

One of many sources, but you forgot that part.

That's the problem with ty 9-11 conspiracy websites.

ONE bit gets picked up and posted as fact in every one of them as gospel.

The fact that 100 people say the sky is green, does not prove the sky is green.

That is a logical fallacy, by the way.

[RandomGuy]

So tell me RG, how did each floor of all three towers meet the necessary temperature for simulaneous truss collapse? Otherwise, explain to me how the buildings all fell at free fall speed again?

Why did the second building to be hit collapse first?

[RandomGuy]

Your assuming that the top of the building came down in one huge load-bearing piece, which every video of the collapse shows not to be the case. The top part of the building crumbles into millions of little pieces many of which fall off the side as it hits the lower part of the towers that are still standing, other which are unexplainably shot hundreds of feet away from the footprints of both towers. This all requires huge amounts of energy, neither of which your calculations have accounted for, RG.

One building collapsed in essence as one piece, and the other had some central failure.

Either method of collapse will still give enough mass to collapse the building.

Remember that kinetic energy increases at a SQUARED function of velocity. A little bit of velocity equals a LOT of kinetic energy.

[RandomGuy]

This is why I keep repeating that the pancake theory is bogus, this was posted by FWDT on page 5. So if the concrete didn't pancake, what happened to it?

The pancake theory actually depends on the floor/outer wall joints coming apart which is not what happened.

The actual collapse mechanism, especially at the beginning depends on the strength of those joints, as the sagging interior sections start pulling sections of the face inward.

This is very aptly demonstrated by pictures that show sections unaffected by the initial jet impact bowing inwards.

[RandomGuy]

Evidence of molten steel was found at the very base of the WTC towers, and is a matter of public record. Still the implications are clear: such a melting of a section of all the inner core box pillars is possible, using relatively simple technology. Such compounds could have been applied to the interior or the exterior of even the largest of these columns in a surrep ious manner, to accomplish the task of melting and collapse. The amount necessary for complete melting of a segment of even the largest box column was calculated, and found possible. Of course complete melting was not necessary to cause total truss failure: a lesser amount of a thermite-like compound could have been used to raise the temperature of the steel to a point where the columns would fail before melting, although some melting must have occurred to account for the steel pools.

That evidence was taken of a picture of molten metal that was presumed by 9-11 conspiracy theorists to be molten steel.

Were there other metals in the towers, other than steel?

Yes.

IF this is the case, can one logically conclude that any molten metal at the site was steel?

No.

There are even eyewitness accounts of people saying they saw "molten steel".

Did they see molten steel or molten metal?

It is a huge speculative leap to think that any molten metal is steel without actually running it through a sprectrograph.

Don't pull the "my guess is an absolute fact" bull with me.

[Nbadan]

The NIST report completely fails to deal with the important dynamic aspects of the tipping of WTC 1 & 2 since the Final Report only deals with tipping as a problem of STATICS. NIST's "global collapse ensued" mantra is a total cop-out, whereby the problem of the collapse is abandoned before it has begun!

To make matters worse, NIST give TWO descriptions of the pre-collapse events: one where the upper section tilts BEFORE collapse, and the other where the upper section TILTS AND FALLS at the same time. I guess NIST had too many authors.

Even Bazant and Zhou (B&Z) do a better job than NIST on this problem since they at least consider the ANGULAR VELOCITY, d(theta)/dt, of the upper section of the South Tower. Their formula shows that, for a given angle of tilt the angular velocity depends on SQRT {3g/h)} where h is the height of the upper section. Hence the rate of tipping is fixed by the dimensions of the upper section. B& Z's formula is ok but it uses an approximation for the moment of inertia, I, of the upper block that ignores the WIDTH of the Tower. Fortunately, it is a simple matter to correct this using I = 1/3 M{h^2 + 1/4w^2} where w is the width of the Tower. If this improved formula is used, reliable values of d(theta)/dt may be calculated for any tilt angle. Integration of the equations also allows the time to reach a particular tilt angle to be derived.

TROUBLE IS, THESE THEORETICAL TIMES ARE MUCH LONGER THAN THE OBSERVED TIMES (which may be measured quite accurately from any of a number of available videos)

So, the bottom line is this:

The top section of WTC 2 tipped at a FASTER angular velocity than is physically possible for a body freely rotating about a pivot at its base!

Now add in some resistance to the tipping from column loading and the problem only gets worse!

I would therefore ask all of you sheeple story fans out there to put away those finite element calculations for a while and check this out..... then please explain how the top of WTC 2 tipped so fast.

[RandomGuy]

Well, gotta jet.

Here is my prediction for all to see:

Dan or some other CTer will come up and say my calculations don't take into account one thing or another, and try to think of some way that they can explain away the very basic physics I have brought up.

Not ONCE will they ever admit that they have not applied the same scrutiny to the "9-11 Physics" calculations.

In the end, because my calculations are inconvenient, they will be called "meaningless".

http://www.physicsforums.com/showthread.php?t=167050

The one guy who seemed to have some good topic knowledge seemed to think I was on the right track.

So "truth" movement will simply prove that it is not interested in the truth, but rather with whatever will reinforce their existing beliefs.

If they encounter something outside of that, or worse yet, something that directly proves something in their worldview to be provably wrong, they do what any religious zealot does.

"BAH! Your "science" is meaningless."

This is a RELIGION to them, and I commit the worst form of blasphemy for questioning it.

In the end, I will simly remind y'all that it took me VERY little research into physics tutorials to get to my calculations. ANY of you can do the same, and there are a LOT of websites that provide excellent tutorials.

Later gaters.

[Nbadan]

he buildings didn't fall at free fall speeds, the pictures clearly show they didn't.

Controlled Demolition Expert and WTC7 (original sub les)

Experiment shows that WTC Bldg. 7 fell at free fall speed

[RIP CITY.]

Where is the energy coming from directing matter skywards?

A "gravity collapse" does not suddenly turn into a large scale explosion and project matter in all directions, nor does it generate a siesmic e. It takes energy to project matter upwards and outwards.

Not only that, But some of the heavy steel beams were found sticking out the windows in other buildings further away and could only have traveled that far due to explosives. I wonder what dunker has to say now?