ok, I wasn't going to weigh in here... although I do think that there needs to be much more discussion of 9-11-2001 and it does not need to involve blowing up of buildings... but first, that was such an atrocious misuse of physics that LondonLad quoted, I really don't know where to begin. Pehaps with a simple demonstration... take a straw, place it perfectly upright on a table, and press down, it is remarkably strong. Wiggle your hand a bit and keep pressing, and it will collapse. Any lateral forces (of which there is a lot when you have the chaos of a collapsing building) will cause a dramatic effect upon a structure designed primarily to support vertical forces. People spouting such utter ridiculousness is a primary way of getting a topic classified as a "don't go there" topic.

But, what happened on 9/11 does need to be discussed, and in ways Glenn could discuss keeping within his interests and expertise. Was there a plan by members of the Bush administration to simply look the other way when told of impending threats with the knowledge that eventually an incident would happen which would allow them to control the media and public opinion for their own purposes? Why is no direct comparison allowed of the perpetrators of 9/11 picking very specific targets to attack the captains of industry and the military leaders whose decisions lead to our military interference in the middle east which targeting decisions led to thousands of innocent civilians being killed on 9/11 as morally equivalent to our/Israeli military bombing a building "hiding a terrorist leader" even if it is known to contain dozens of children and other innocents?

At this point, we have directly killed or indirectly caused the deaths of at least 100 innocent people for every innocent person killed on 9/11/2001, with that tragedy being explicitly invoked to justify such horrors on our part, horrors which were planned well before 9/11/2001. Israel is following our lead and doing the same in Gaza, with the United States government (OUR representatives) claiming that it is "morally acceptable". What the Bush administration knew and did not act upon... or worse yet may have knowingly encouraged in order to give an awful, illegitimate administration (remember, the Bushies, now without a doubt based on actual counts of the votes, did LOSE the election of 2000) the political and public support to carry out their awful agenda at home and abroad. There really is no need to invoke stupid theories of blown up buildings to ask the important questions surrounding the circumstances of that tragic day.

Have you ever solved a physics problem? The text made a specific, specious physics argument. The straw example is a demonstration of why the physics argument quoted by you is not valid, since gravity is explicitly a vertical force, and in the collapse of the building the forces involved are chaotic and so the simple downward force of gravity is not all that is acting on the lower portions of the building. In fact, any such chaotic physical system is extremely complicated to model, and the facile explanation given by you is a perfect example of misleading through misuse of physics, which, as a physicist, I find reprehensible and my duty to correct. Since my simple demonstration with the straw gives an example of how the vertical structural strength of a building in such a situation and the net downward force is irrelevant even in a very simple situation when you allow for some lateral forces, it gives a simple to understand demonstration of how the argument you gave is not generally valid.

Now, there may be other things that your video shows which would lead to questions about the cause of collapse, but your "explanation" about the rate of fall "proving" that something else caused the collapse is just completely bogus.