Originally Posted by

**TruthSeeker1234**
I agree. The 9 second figure is NIST, not me.

Quote:

At 9:58:59, the South Tower collapsed in ten seconds,

source No estimated stated for North Tower.

http://www.google.com/url?sa=t&ct=re...4F0RvDFt5J23xw : No estimates provided for collapse time.

http://www.popularmechanics.com/scie...tml?page=5&c=y 8-10 second estimate, based upon seismic data

http://www.jnani.org/mrking/writings...#_Toc144445996 rebuttal to Jones' collapse time argument

http://www.911myths.com/html/wtc_col...estimates.html collapse time estimates 8-14 seconds

Height of towers Height (ft) 1,368

source
Let's check this, for freefall, in a vacuum we use X=at^2/2 or X= .5*a*t^2 where X=distance, a=9.8 m/s^2 and t=time.

http://www.lerc.nasa.gov/WWW/K-12/airplane/mofall.html
X=.5*a*t^2

X=.5*9.8*t^2

X=4.9*t^2

0 seconds => X=0

1 seconds => X=4.9m

2 seconds => X=19.6m

3 seconds => X=44.1m

4 seconds => X=78.4m

5 seconds => X=122.5m

6 seconds => X=176.4m

7 seconds => X=240.1m

8 seconds => X=313.6m

9 seconds => X=396.9m = 1028.87139 feet

9.25 seconds => X=419.25625m = 1375.51263 feet

9.5 seconds => X=442.225m = 1450.86942 feet

10 seconds => X=490.0m = 1607.61155 feet

Now, please cite exactly where NIST said it fell in exactly 9 seconds.