On 3/15/07, Jed Rothwell <[EMAIL PROTECTED]> wrote:
John Berry wrote: >Ahuh, and yet no details are ever availible. That is incorrect. NIST has published thousands of pages of data. Please do not dispute matters of fact. >I'm not questioning if when a floor is pulled if further floors >worth of destruction will occur, obviously it will. >The question is in a building such as the twin towers or other tall >conventional buildings if a floor near the top is pulled if the >entire thing will collapse at near freefall speeds. All other buildings destroyed by this method, on purpose or by accident, have fallen at freefall speeds.
Show me the report.
I would expect in the case of the WTC that a lot of it would >collapse, but I would think it might stop 2/3rds of the way down . . . You have that backward. When the floor near the top has enough energy to break the next one down, that adds one floor to the mass of falling material, increasing the total mass that strikes the next floor down. After ten floors collapse you have 10 floors worth of additional mass falling down.
But falling from what height? Each new floor falls a total of one floor and it must break the walls in doing so before it has to help take out the next floor, overall each floor should slow the descent. Free fall speeds means 0 resistance, and yet no one can deny the work done. You are also ignoring the far better evidence, such as explosions heard and caught on tape, squibs clearly visible and undeniable, the glass broken on the ground floor when the firemen arrived, and indeed seismographs recorded events before the first plane hit which agrees with what those in the buildings report of bombs in the basement. People thrown about and burnt by explosions. Tiny pieces of bone found on roofs of distant buildings, how can such tiny pieces of bone be flung so far by a collapses under gravity? You are ignoring building number 7 where squibs are plainly visible before the building collapses, and the BBC talk about it's demise with it standing in the background 22 minutes before hand, and this is only some of the building related evidence of explosions. This is not quite true, because some of
the material falls out the sides and straight down, but most of it joins the total mass of falling material, and adds to the force of the reaction.
It's not weight that is important, it is the KE and there is no way it can fall at freefall speed as it needs to constantly do work to destroy the floors below, new floors being added to the falling mass start out with no KE. Show me a video or at least a report of a tall building with the top 3rd falling through the rest of the building at freefall speeds without the building being otherwise weakened Two-thirds down you have *far* greater force striking
each additional floor, and much greater damage. If anything, it should go faster. >, and at the very least to occur far more slowly than freefall >speeds which means that the building offered 0 resistance which is >at odds with the conservation of energy. As Stephen A. Lawrence already pointed out on this forum, the breaking reaction occurs at the speed of sound. A floor either breaks or it does not break within a fraction of a second. The energy absorbed by the breaking is absorbed in that fraction of a second and the reaction continues nearly as quickly as it would in free fall.
Energy is absorbed, the KE of the upper portion of the building is absorbed as it impacts with the floors below as you stated, and yet it can't still have the same KE it would have had if it had indeed been in freefall, and yet somehow it does. You can see from the 9/11 photos -- and from the photos of other
buildings deliberately destroyed by this method -- that the speed is a little slower than free fall. Material thrown out the side hits the ground a little sooner than the falling bulk of the building. - Jed
