BTW, when you add in the additional 7 seconds for the global collapse time, the free-fall / high speed argument is invalidated as well. I'm sure this has been pointed out to you many times on more than one thread.
That's false!
There is often a discussion about the collapse time of wtc7. The movement of the penthouses adds some seconds. That's very interesting indeed, the 6.6 seconds is the fall of the roof of wtc7 and not the penthouses. If we only look at the fall of that roof, then the discrete crush-up model gives the following plot
Here horizontally we have the collapse energy per story (assuming the mass of the building is scaled to 1) and vertically the collapse time. I made this plot with maple a couple of weeks ago, the derivation is straightforward. Shagster (not here) got the same result using differential equations using an homogeneous model, i.e. in fact the Bazant/Greening
crush-up equation with Stretch ignored)
This follows from maple:
E1/M=0 J/kg => T=5.96 seconds
E1/M=4.19 J/kg => T=6.5 seconds
E1/M=4.83 J/kg => T=6.6 seconds
E1/M=8.17 J/kg => T=7.38 seconds
Indeed for E1/M=0 we see that the buildings collapse time is exactly the free fall time sqrt(2*174/9.81), about 5.96 seconds. Since the sucker came down in 6.6 seconds that implies that the ratio is E1/M=4.83 J/kg, and here E1 is the collapse energy per story and M the total mass of wtc7. In this way it is possible to fit the ratio although the individual values are not known.
The nice thing is that in Greening's model (and also Bazant of course because that is in fact the continuous model) the collapse time is scalable, which means that for the total collapse time T (and also the speed as function of the floor, or time)
we have
T(a*E1,a*M)=T(E1,M) , for some a>0 (also valid for wtc1,2)
When the value of the mass seems to be half as much as we thought then the E1 value should be modified in order to get the ratio unhanged (to keep the collapse behaviour the same)
A consequence of the crush-up model is also that it must be a fast collapse if it is a complete one. For E1/M=8.17 J/kg the maximum collapse time is reached, when that value is higher the collapse will not be complete (the collapse time becomes mathematically complex)
and a story will be left. Therefore if you add the collapse time of the penthouses then you have a problem in the 1d crush-up model.
This shows that the initial movement indicates that the structure is failing, it cannot be a part of the crush-up. Another important thing about this is that this failed, broken and falling building provides huge resistance, in spite of the fact that it is demolished inside before the global collapse. For the wtc1,2 we had the planes, we had toppling blocks, initial movement, but not for wtc7.
How much kinetic energy do you want to crush an initial story ? There is no basis for a collapse.
Of course, this contradiction- like many others in your absurd claims- will go unresolved yet repeated for some time to come.
