Common sense tells me that NO building can fall at free fall speed unless there is absolutely no resistance provided by the support structure (wood, steel or silly putty) for the building.
Explosive demolition of all the support structure DOES explain how the two towers and WTC 7 collapsed at free fall speed.
Related points that have not been explained:
> there was molten metal at ground zero days after the towers collapsed
> at least one of the pictures of ground zero show metal supports (huge I-beams) that have been severed diagonally – this is a standard part of controlled demolition which is accomplished using shaped thermite charges – the diagonal cuts cause the building being demolished to ‘walk’ off its supports – the supports at ground zero weren’t bent or torn which is what I would expect from a non-controlled collapse
