NIST's demise at freefall speed

Question: If we cut both cables at the same time, which block will reach the ground first? Answer: According to NIST, both blocks would reach the ground substantially at the same time. The healthy floors below the falling block on the left, according to NIST, didn't offer any particular resistance nor did they slow down in any way its path towards the ground. As the 9/11 Truth Movement kept asking for clarifications, in September 2007 NIST answered: "We are unable to provide a full explanation of the total collapse." (Page 4, top par.) In other words, NIST maintains that an event against the laws of physics took place, while being unable to explain how it could have happened.

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WTC 1 e 2 As earlier remarked by Prof. Steven Jones, one of the things the official version and the Truth Movement agree on is the dynamics of the collapse of the Twin Towers.

NIST maintains that the block of floors above the impact area, for both Towers, substantially fell to the ground through the eighty-plus healthy, remaining floors below (see point #5 here).

This statement appears in the NIST NCSTAR1 Final Report, which represents, for all means and purposes, the government's official version for the collapses of the Twin Towers.

From section 6.14.4 of the document we read:

"the structure below the level of collapse initiation offered minimal resistance to the falling building mass at and above the impact zone. The potential energy released by the downward movement of the large building mass far exceeded the capacity of the intact structure below to absorb that energy through energy of deformation. Since the stories below the level of collapse initiation provided little resistance to the tremendous energy released by the falling building mass, the building section above came down essentially in free fall, as seen in videos. As the stories below sequentially failed, the falling mass increased, further increasing the demand on the floors below, which were unable to arrest the moving mass."

The disagreement rests on the reason for this event.

A passive collapse (due to gravity only) cannot proceed essentially in freefall speed through the path of most resistance (represented by the 80 plus healthy floors below).

A passive collapse can indeed proceed at freefall speed, but only by taking place on the side of the building, where it only encounters air.

Or it can proceed through the path of most resistance, but not at freefall speed, because of the continuous impacts with the obstacles in its way.

You simply cannot have it both ways.

NIST instead has also reaffirmed the concept in the FAQ on their official website, stating that:

In other words, the momentum (which equals mass times velocity) of the 12 to 28 stories (WTC 1 and WTC 2, respectively) falling on the supporting structure below (which was designed to support only the static weight of the floors above and not any dynamic effects due to the downward momentum) so greatly exceeded the strength capacity of the structure below that it (the structure below) was unable to stop or even to slow the falling mass. The downward momentum felt by each successive lower floor was even larger due to the increasing mass.

From a strictly scientific point of view, we know that a gravitational (passive) collapse counts on potential energy only. If such energy is converted entirely into kinetic energy -- i.e., to accelerate the falling block to practically freefall speed -- there is no energy left to break the joints of the remaining 80 plus floors below. Let alone to pulverize the concrete floors into the fine dust we have all seen from the WTC.

To state that this is possible is tantamount to violating the Principle of Conservation of Energy.

As shown in the drawing above, this paradox should be evident even to a nonscientist.

Imagine WTC-1 in the condition it was moments before it collapsed. The top 12 floors are hanging above the 6 missing floors (those torn apart by the plane) and the remaining 92 healthy floors below.

Next to it let's place a similar block hanging in the void, with absolutely nothing below. Cut both cables at the same time, and try to imagine which of the two blocks will reach the ground first.

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WTC 7

NIST NCSTAR1A represents the government's official version for the collapse of WTC7.

The document was published in draft form in August 2008, then in its final version 1 month later. During that interval NIST was able to evaluate the comments submitted by the readers and eventually modify and correct the final document.

Among the modifications introduced in the final version there is one specifically addressing freefall speed. The issue was brought up by Davey Chandler of AE 9/11 Truth, who underlined both the oversimplification and the actual mistakes in the method used by NIST to establish the total time of the collapse.

Originally NIST used only the start and ending point of one particular video as a reference for the total time of the collapse, concluding that such time was 40% higher than the time of freefall speed.

A more detailed, frame by frame analysis by Chandler, who used an appropriate software, has shown that WTC 7 did in fact experience a freefall acceleration.

NIST has then corrected both their analysis and their conclusions, even though it forgot to list the changes in the modifications reference sheet between draft and final version.

As we can read on page 48 of the final version:

Thus NIST has acknowledged that building collapse experienced a stage of full freefall speed, meaning that either the structure below offered no resistance to the fall, or that it was removed altogether.

As already clarified before, if the potential energy is fully converted to kinetic energy, there is no energy left to perform other tasks, such as breaking the joints of the eight floors, simmetrically and at the same time.

According to Physics, the energy to perform such tasks must necessarily have originated from an external source. (NOTE: the eight floors marked in the drawing have been chosen arbitrarily, as NIST did not indicate precisely which ones they were).

To avoid further confusion, it should also be noted that:

1 - NIST has excluded the possibility that the presence of the Con Edison substation could have played any role in the collapse.

2 - Even though WTC-7 was hit by falling debris from Tower One, NIST has excluded that this could have played any role in its collapse. (The debris, according to NIST, only started the fires, but didn't influence directly the collapse.)

Both issues are addressed in the same document above, on page 48

3 - Furthermore, it must be noted that NIST as excluded the possibility of one large explosive device as the cause of the collapse.

The hypothesis of multiple explosive devices, just as that of linear shaped charges, have not been considered, even though this would be the most plausible choice in a controlled demolition of a steel framed building, according to experts.

Riccardo Pizzirani (Sertes)