The towers didn't fall at free fall, what you're seeing is debris.
The debris are falling with each floor. With the exact same rate of gravity.
What was the coefficient of friction for each floor?
WTC 7 was hit by debris from the falling towers like many of the buildings surrounding the twin towers. However, it was also the victim of a fire fed by diesel fuel
Debris damaged the superficial structure, not the Steele frame structure. There is no evidence to show it was damaged, except for some minor fire.
Fire can't bring down a building, it might weaken the steel in its surrounding, but not melt EACH and every steel structure for each floor enough for the building to implode in its footprint at the same rate of gravity.
The whole debate over the "melting point of steel" is deceptive as fire doesn't need to melt something to weaken it. For instance metal warps and expands when heated.
It might weaken it, but not melt it for it to give away. If it did, you would see more buildings fall due to fire. Which has not happened ever before, let alone 3 times in one day.
Also, it can not weaken every single steel structure from top down.
Note that the above link is talking about why jet fuel didn't need to melt the steel of the two towers, but the the principles apply to WTC 7 as well.
It will weaken it, but not melt it. If it can not melt it, how could there be molten steel found at the very bottom of the pile of debris?
This has lead many to believe thermite was used.
Again, if fire weakens steel enough for a steel structure to give away, how come it has never happened before to much weaker buildings.
Also, not all the steel framework would be weak and would cause resistance.
Simple question, what was the coefficient of friction for each floor. If it showed resistance, how much was it, if you negate air friction.
It was zero, because each floor was taken out right before the one from the top met it. That is why it continued to accelerate downwards in its own footprint.
Except that's not the case, there is damage to the Pentagon, you can even see pictures with bits of engine in the Pentagon.
There is no damage from the engines of the planes, non.
There is however a video of a missile hitting the pentagon.
Popular mechanics is a mass media network show, there is no credibility in the same media which sold you WMD's in Iraq.
http://www.ae911truth.org/