I've attached position v. time data from a CNN video of the collapse of WTC
North Tower cut from an Excel spreadsheet. The columns are 1) time from
beginning of video clip in seconds, 2) horizontal pixel, 3) vertical pixel,
4) horizontal position in feet (pardon the English units), 5) vertical
position in feet, and 6) the vertical position in feet (adjusted to account
for changes in the tracked object).
At 1.9135 s, 3.6592 s, 4.2635 s, I had to switch object to track, because
the first either left the frame or was obscured by dust. The pixel
positions of the old and new objects at that time are indicated. I
initially tracked one top corner of the tower, then points on the antenna mast.
The first two rows indicate data to determine the scale. I chose two
points with the same elevation at the corners of the tower on the side
facing the camera. The tower is rotated slightly about the vertical, but
not by much. The 9/12/2001 edition of the St. Louis Post-Dispatch lists
the sides of the square towers as "approximately 208 ft." The "scale" is
in feet/pixel.
Column 5 values at 2.35 s, 3.29 s, 3.3235 s, and 4.5321 s were padded with
zeroes just to make the columns in this message line up properly.
The video runs for about a second before the tower begins collapsing, but
there is still about 4 seconds of data here.
The Excel best fit 2nd degree polynomial for the adjusted vertical position
v. time after 1 s is
y = -10.811x2 + 10.691x + 0.0264 with R2 = 0.9978
This data may be used freely only for noncommercial personal or educational
purposes.
I look forward to any comments regarding or findings resulting from this
data. Enjoy.