RE:Brace Yourself for the coming weeks ahead, FolksHeavy sigh. It's been a few years since I have responded to to a 9-11 conspiracy theorist but I'll take a swing at it.
I have been involved in steel construction and heavy construction my whole professional life so I do have some backround in the "controlled and planned event" information of 9-11 that you mention.
A few facts....steel loses 50% of it's strength at about 1100 degrees (F), Burning paper burns at up to 1500 degrees (F) and kerosene about 1500 degrees (F). Much of the steel was stripped of its fireproofing by the plane impact. We camber (bend) steel beams at about 1000 degrees. Structural design of a building such as that has numerous safety factors incorporated in the design but there is not enough safety factor to overcome a 50%+/- loss in strength due to heat and who knows how much damage was done by the impact. The millions of tons of building, above that floor was going down.
Why did it fall straight down and the floors below did not slow it down? It fell straight down because there was nothing to push it sideways, is the simple answer...and the floors below offerred no resistance at all to the falling floors above once they got moving. An easy example is if you lay on the floor you can easily hold a 100lb weight on you chest...right? Ok, let me take that weight up 10-11ft above you and drop it on your chest...ouch. You didn't mention the explosions at each floor prior to the floor above hitting the floor below. They weren't explosions...they were debris being blown out as the space between the upper floor and lower floor shrank and compressed the air. Experiment-put flour on your two hands and clap them together (close your eyes)...same thing.
Now WTC7.....look very closely at where the collapse starts....watch the HVAC units on the roof. It starts on the back side of the building away from the camera view. Next see what video you can find of the damage on that side of WTC7 (that faces the fallen buildings) and fill everyone in on what you find.
I apologize for carrying this on way too long.
Ken