25-08-2013, 05:16 AM
Lauren Johnson Wrote:Quote:the rapid horizontal propagation across the 98th floor of the North Tower.
Tony, I believe you said this propogation was 1/250th of a second? How did you calculate this?
Lauren, I said the horizontal propagation across the 98th floor in the North Tower occurred in 250 milliseconds in one of my e-mail answers to Jeffrey. That would be 1/4 of a second, as there are 1,000 milliseconds in a second.
The calculation was based on measurements of the fall of the corners of the building and the frame rate of the video being used for the measurement. The video frame rate was the standard 29.97 frames per second, so each frame is 33 milliseconds.
The calculation has varied between 250 milliseconds and 500 milliseconds depending on who is doing it and their measurement accuracy. Even accounting for a small error, it is clear that the propagation occurred very rapidly and was most certainly less than a second. This is significant when one realizes there is 293 feet between diagonal corners in a building which is 207 feet long on each side.
Watch this short slow motion video to see how uniform the smoke comes out and how evenly the upper section comes down at first http://www.youtube.com/watch?v=y9-owhllM9k.