I gotta mention this "free fall speed" isn't, there is such a thing as free fall acceleration. 9.8 m/s^2 defines a rate of acceleration.
Have you taken the time to actually attempt to measure the rate of descent? The NIST had modified their final report based on measurements of the acceleration of WTC7, You can choose to simply not accept what is fact about the fall of WTC7 but that doesn't change anything.
So what happened with the other 519 feet of the building? What about the mass of the collapsing building..At what rate would it be falling?
In all likelyhood, the top 519 ft descended and reached a speed of aprox 60 mph before impacting the ground and the force caused the destruction of the upper 519 ft of WTC7, the speed is only an estimate off the top of my head, if somebody actually does the calculations and states that its closer to 50, so be it, you gonna shoot the messenger .... or? and as for the mass of the falling bit, that may be an interesting number to dredge up, but really its not necessary to know, in order to understand what happened.
/truther mode on But genericBob, a car crashing into a wall at 50 mph doesn't completely destroy itself! How can this be? How can a steel structure do that to itself???!!! /truther mode off
false! part of the north face of wtc7 fell for 2.25 sec not the whole structure. 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 and define 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 Section 3.6 of the final summary report, NCSTAR 1A (released Nov. 20, 2008; available at http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR 1A.pdf) and detailed in Section 12.5.3 of NIST NCSTAR 1-9 (available at http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR 1-9 Vol 2.pdf). 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 timecompared to the 3.9 second free fall timewas 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. http://www.nist.gov/public_affairs/factsheet/wtc_qa_082108.cfm
generiBob and the rest will probably ignore the above as usual. What I want to know is that if explosives equals no resistance equals free fall, then what was the 1.75 seconds worth of non-freefall when when the explosives supposedly went off simultaneously?
Here is what we have: in order to have anything fall at 9.8 m/s^2 it has no resistance under it, and since the whole 300 ft wide North Face of WTC7 fell as a unit, that indicates the support would have to be all removed all at the same time. This isn't rocket science, what part of ALL resistance removed and all at the same time do you not get?
your point? 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
May I ask as to exactly what sort of conditions need to happen in order to get a building to fall in the way that WTC7 did? The fact is that in a controlled demolition, the engineers work on this very hard, the figure out in great detail how the structure will come down, and then they have explosives placed in precise locations to do the job and these explosives are set of at precisely the proper time to do do the job, now people are alleging that its possible to get the very same result of all this precision work, from random damage & fires, do you see what is being promoted here?
It's not even close to the 'very same result'. For one example: WTC7 fell well outside of its footprint, damaging other buildings in the process. This is not the case in a controlled demolition.
so you deny the factors A: the total destruction of WTC7 B: the 2.25 sec of free fall that can only be the product of planning, that is somebody intended it to happen exactly that way.
all of those statement are false. a. wtc7 collapsed leaving a huge pile of debris so your use of the phrase total destruction is a misnomer ( examples of total destruction Hiroshima, Santorini, Pompeii just to name a few ) b. the 2.25 sec of freefall reveals nothing but for that minuscule fraction of time some of the north face was unimpeded. so there...
Marvin had zero to do with this event. You've been shown this already, Boss. (I know, gotta keep your quota up)
Would you then say that a building was removed by controlled demolition was therefore NOT destroyed because it was not like the buildings destroyed at Hiroshima? Compare the pile left after the destruction of WTC7 with the aftermath of any controlled demolition. Get the picture? and the 2.25 sec of free fall is relevant in that it demonstrates the fact that for the 2.25 sec, the falling mass had no resistance under it, how is this sort of thing caused by random fires? "progressive collapse" no, not at all, if it were a progressive collapse, things would follow a progression and the building would not have an event where a large mass as was observed fell at free fall for 2.25 sec. How do you get ALL of the resistance removed out from under all that mass, and all at the same time?
