NIST ADMITS FREEFALL
NIST ADMITS FREE FALL (WTC 7)
NIST admits that WTC 7 fell at free fall acceleration for 2.25 seconds for just over 100 feet. For this to happen all structural supports have to be eliminated at precisely the same time. Something that fire alone could never accomplish. This is a physical impossibility without the aid of some type of energetic material.
Buildings do not pass through the path of greatest resistance at the same rate as a bowling ball falls through air.
WTC7: NIST Finally Admits Freefall (Part II)
David Chandler’s – WTC7 NIST Finally Admits Freefall FULL
11. In a video, it appears that WTC 7 is descending in free fall, something that would not occur in the structural collapse that you describe. How can you ignore basic laws of physics?
“In the draft WTC 7 report (released Aug. 21, 2008; available at http://wtc.nist.gov/media/NIST_NCSTAR_1A_for_public_comment.pdf),
NIST stated that the north face of the building descended 18 stories (the portion of the collapse visible in the video) in 5.4 seconds, based on video analysis of the building collapse. This time period is 40 percent longer than the 3.9 seconds this process would have taken if the north face of the building had descended solely under free fall conditions. During the public comment period on the draft report, NIST was asked to confirm this time difference anddefine the reasons for it in greater detail.
To further clarify the descent of the north face, NIST recorded the downward displacement of a point near the center of the roofline from first movement until the north face was no longer visible in the video. Numerical analyses were conducted to calculate the velocity and acceleration of the roofline point from the time-dependent displacement data. The instant at which vertical motion of the roofline first occurred was determined by tracking the numerical value of the brightness of a pixel (a single element in the video image) at the roofline. This pixel became brighter as the roofline began to descend because the color of the pixel started to change from that of the building façade to the lighter color of the sky.
The approach taken by NIST is summarized in NIST NCSTAR Report 1A, Section 3.6, and detailed in NIST NCSTAR Report 1-9, Section 12.5.3. The analyses of the video (both the estimation of the instant the roofline began to descend and the calculated velocity and acceleration of a point on the roofline) revealed three distinct stages characterizing the 5.4 seconds of collapse:
Stage 1 (0 to 1.75 seconds): acceleration less than that of gravity (i.e., slower than free fall).
Stage 2 (1.75 to 4.0 seconds): gravitational acceleration (free fall).
Stage 3 (4.0 to 5.4 seconds): decreased acceleration, again less than that of gravity.
This analysis showed that the 40 percent longer descent time—compared to the 3.9 second free fall time—was due primarily to Stage 1, which corresponded to the buckling of the exterior columns in the lower stories of the north face. During Stage 2, the north face descended essentially in free fall, indicating negligible support from the structure below. This is consistent with the structural analysis model, which showed the exterior columns buckling and losing their capacity to support the loads from the structure above. In Stage 3, the acceleration decreased as the upper portion of the north face encountered increased resistance from the collapsed structure and the debris pile below.”
Questions and Answers about the NIST WTC 7 Investigation
(09/17/2010, ARCHIVE, incorporated into 9/19/2011 update)
Section 12.5.3 of NIST NCSTAR 1-9
“11. In a video, it appears that WTC 7 is descending in free fall, something that would not occur in the structural collapse that you describe. How can NIST ignore basic laws of physics?”
P 87/130 NIST
Final Report on WTC 7.
“In stage 2, the north face descended at GRAVITATIONAL ACCELERATION, as the buckled columns provided neglibile support to the upper portion of the north face. This FREE FALL DROP continued for approximately 8 stories or 32.0 m.”
“In its draft report, released in August 2008, NIST attempted to cover up evidence that WTC7 fell at freefall, but the coverup was transparent. In its final report, released in November 2008, NIST finally acknowledged freefall, but couched it in a bizarre framework that continues to deny its clear significance. This video displays the brazenness of the NIST WTC7 coverup.”
NCSTAR 1A 3.6
“This free fall drop continues for approximately 8 stories”
“the distance traveled between t=1.75s and t=4.0s”
“constant, downward acceleration during this time interval.”
“This acceleration was *9.8m/s^2*, equivalent to the acceleration of gravity.”
2/25/11 Answers from NIST to Questions by Chris Mohr,
Debunking NIST’s August 21, 2008 Final Report on WTC 7
2/25/11 Answers from NIST to Questions by Chris Mohr, Journalist
Questions and Answers about the NIST WTC 7 Investigation http://www.nist.gov/el/disasterstudies/wtc/faqs_wtc7.cfm
“Also included in the graph is a linear regression for approximately 2.6 seconds of the collapse that appears to have a constant acceleration. As can be seen, the slope (acceleration) during this portion of the collapse was approximately constant at about 9.8 m/s/s, or acceleration due to gravity with little to no resistance below. The r-squared value for this linear regression analysis was 0.9931 – a very good fit. This clearly demonstrates that NIST is being extremely misleading in reporting to the public that the structure did not descend at free-fall speed, especially given the implications of this documented feature of WTC 7’s destruction.”
BBC tried to debunk the free fall collapse of WTC 7 but had to retract when NIST admitted to it.
9/11 Truth Versus The BBC (@12:15)
“5.4 seconds depends on an artificially early start time…..”