David Chandler: The Simple Physics of the World Trade Center collapses

Just how fast is free-fall acceleration? And what does it mean when a building collapses that fast? My guest on RichardGage911:Unleashed! brings you back to high school and shows how easy it is to talk to your friends about the problem of World Trade Center Building 7. David became involved with studying the building collapses at the World Trade Center when he realized that he could use the video frame tracking software that he used in his physics teaching, to measure various velocities and ...