Conclusions

1. Timing estimates of the total horizontal force show it to be about an order of magnitude larger than the force of gravity. It could be even larger depending on how large the force is that breaks the 2 segments of the building apart is.

2. A lab exercise to estimate this horizontal force from photo measurements and simple equations of motion could readily be introduced into an introductory mechanics courses for science, engineering, and & health majors, presenting an important application of these concepts.

3. Notes for this paper, including links to all 12 slides, are online at:

	www.SeaLane.org 


(in the Writings section).

Bibliography

1

Grabbe, C.L. (2008a) "Analysis of the Collapse of the South Tower of the World Trade Center" American Physical Society April Meeting, online at:
http://meetings.aps.org/Meeting/APR08/Event/84051

2

Grabbe, C.L. (2008b), "Response to NIST on Energy and Momentum," J. 911 Stud. Jan. 29 Letter, online at:
http://www.journalof911studies.com/letters/g/GrabbeToNISTenergyMomentum.pdf

3

Jones, S.E., J. Farrer, K.R. Ryan, D. Farnsworth, F.M. Legge, G. Roberts, J.R. Gourley, and B.R. Larsen, "Investigation of Red/Gray Chips Observed in the Dust from the 9/11 World Trade Center Catastrophe," submitted for publication, 2008.

4

NIST NCSTAR-1, Final Report on the Collapse of the World Trade Center Towers (US Government Printing Office, Washington, DC, 2005).

5

NBC film of South Tower collapse on 9/11/01, online at:
http://911research.wtc7.net/wtc/evidence/videos/index.html