Physics of World Trade Center collapse

As we all know, on September 11, 2001, two planes struck the twin towers in New York City causing their collapse. What some people don’t know is that another building fell that day, a building located at 7 World Trade Center. The cause of its collapse is heavily disputed still today. Many argue that the building collapsed after fire from the neighboring Trade Center caused the steel to melt, compromising its structural integrity. This is what the national reports claim caused the fall. But according to this video, and many other conspiracy theories, something else was at play here.

http://www.youtube.com/watch?v=7wI1BNgXskM

This video explains the argument many physicists about the building’s collapse. As you can see in the video, the initial collapse was in column 79. Shortly after, the remainder of the building falls down simultaneously. If the framework of the building had melted, it seems strange that the entire building would have collapsed at the same exact time. You can see how the roof line stays intact during the fall. The calculated values of the acceleration of the building’s collapse, do not match up with the actual time it took for the building to fall. Physicists use these numbers to argue that the building must have been in free fall. In other words, there was no resistance underneath of the building during the collapse. The only way that this could be possible is if there was an explosion underneath, allowing limited resistance for the fall. This theory will probably never be accepted as truth by the national government as it would imply that this was an inside job. - post written by Lauren Dittman.