Originally posted by: Cogman
Originally posted by: kylebisme
Originally posted by: Cogman
And How do you know that the supports were simply not providing negligible resistance?
Rather, I know for a fact that:
Originally posted by: kylebisme
...not only were the north face columns [NIST mentions] not providing any notable support, neither were those of any other face, or all of the mass that made up the floors and everything else in the building [all of which NIST simply ingores].
And I know this because:
Originally posted by: kylebisme
This is simply inherent to the definition of the term free fall, as
documented here:
free fall
?noun
1. the hypothetical fall of a body such that the only force acting upon it is that of gravity.
That said:
Originally posted by: Cogman
Ok, So now we know that free-fall technically doesn't happen on earth.
Rather, it technically doesn't happen anywhere, only:
Originally posted by: Cogman
...in the hypothetical case of a complete vacuum...
And not even the darkest depths of space is a complete vacuum. On Earth, the mass which makes up the atmosphere doesn't provide notable resistance against the fall of a notably denser mass either, at least not until it is falling so fast that even pushing the air out the the way quick enough to keep accelerating requires considerable force. To drop such a dense mass though thin air without having it archive a period of acceleration indistinguishable from free fall, one would need to strap something with a large surface area to mass ratio to it, to act as a parachute.
I'm going to stop at that for now to see if you are clear with what I've said so far. If you have any questions or arguments with anything in this post, please present it, and if not then a simple "agreed" will do, at which point I will move on to addressing another section of your reply. Note that I did skip over your request for the math here, and I've explained why before; the math won't be any good to you until you are comfortable with the principles of physical reality which it describes.
I already provided my argument, and they you got caught up on the fact that I agreed with you that free fall doesn't happen on earth :rolleyes;
In fact, it's laughable because not only did you fail to prove that the columns didn't fail because of weakening, you just quoted your self saying it is impossible.
Maybe you simply don't understand what negligible means. It means that the resistive force is so small that it is hardly worth noting. For example, If one column was full strength and the rest magically disappeared, that column would provide a negligible resistance to the falling structure. It would fail so fast it would make your head spin.
Air isn't the only thing that can be negligible. When the force of the falling object is far greater then the tensile strength of the material it is falling on, the force provided by it will be negligible.
Think of it this way, you have a tower made of toothpicks that is just barely supporting its own weight (generally the case with buildings. They aren't built to hold much more then their own weight really.) Now, with that stack, take the top couple of levels, pick them up about the height of 1 level, and drop them on the stack. What will happen? The stack will fail and the decent of the top stack for a period while the rest of the stack was falling would look to be in a free fall.
When talking about dropping an object, resistive forces act in an exponential fashion. That means that the building falling at 2 m/s might look to be in a free fall while at 3 m/s you reach a sort of maximum velocity. Sure, the time where it is accelerating to 3 m/s may look to be a free fall, but that is because the resistive forces are minimal. compared to the acceleration due to gravity.
And you still haven't answered to the fact that it could have easily been going slightly faster in stage 1. IE it needed to be going 3.2 m/s if it was to descend in a free fall. However, what if it was going 3.21 m/s? all the sudden, I didn't have to be a total free fall and it STILL could have covered the distance that NIST said it did. With that much mass, 0.01 m/s faster makes a HUGE difference on the amount of force applied to the joints. Yet it would be something very hard to measure, especially considering the fact that the frame rate of phones is approx 0.05 seconds / frame. They didn't have high speed cameras capturing the building falling, thus their measurements on falling speeds are going to be semi-rough.
There are plenty of explanations, reasonable and logical to your issue. And you haven't discredited one of them. All you've said is "That's physically impossible!". Prove it.