Yes, it happened to fall at an acceleration that roughly matched g for 2.25 seconds. If you look at Chandler’s Tracker plots, you’ll see that they actually exceed g for some time*, which disproves free-fall; some additional downward force must have been acting upon the outer shell of the building.
If you watch the collapse videos you’ll see a very likely reason for that additional force; as the east penthouse falls through the roofline, an increase in daylight through the structure beneath can be observed. Pretty obviously, the building’s core under the penthouse dropped first, such that the horizontal connections were pulling down upon the outer shell.
* Chandler dismisses such variations as measurement error, but the smoothness of his graph suggests it’s pretty accurate.
– “what was causing it to coincidentally travel at that speed?”
By definition, coincidence doesn’t have a cause; it’s “just coincidence”.
g and free-fall are not remotely similar. Free-fall is a physical condition, whereas g is an engineering constant. The half mile to the shop is just a measurement; it is not the walk.
I can’t imagine how you disagree that the overall collapse took 18-19 seconds; it’s all captured in the video I linked, you’d have to ignore the fall of the east penthouse. And there are videos on YouTube which show WTC7’s collapse side-by-side with known demolitions. At first glance they appear to accelerate identically, but look closer and you’ll see that the zoom has been scaled to make the accelerations match, and WTC7 falls through more storeys in the same time than the demolitions which it is being compared with. Since Chandler measured WTC7 to fall at near g, the known demolitions must be accelerating at less than g, and that is precisely what you’d expect because of the deformation and pulverisation of the materials and the dissipation of energy in the form of sound. Demolitions fall slower than g, so the entire “g must mean free-fall” argument is invalid.