Let’s do a quickie, common sense thought experiment to help understand what the “controlled demolition” theory is trying to say.
The controlled demolition theory rests on the following assumption: “the building was too strong to have collapsed from simple gravity”
Put another way “the building could easily absorb the energy of the falling section and not fully collapse”
Does this pass the common sense muster?
Let’s take an average guy off the street. He can hold a 100 pound bag over his head for a few minutes. Say he is balancing it on his head to make things simple. In terms of physics this means he is providing a force equal to gravity in order to hold this bag motionless.
This is what the lower 80 stories did for the upper 30 stories for 30 years before 9-11.
Now, one story is about 12.32 feet. The thirty floors started falling through the damaged sections, and at least one damaged, weakened floor gave way.
Take that bag away from our average guy and hold it 12.32 feet over his head. Now drop it on his head. What happens?
Ouch is right.
Let’s see how many pounds of force will be applied by that bag to the guy’s head.
KE is measured in joules. KE= ½* mass * velocity *velocity
First let’s convert to metric for ease of calculation.
Mass=45.36 kg
http://manuelsweb.com/kg_lbs.htm
H = 12.32 feet = 3.65 meters
http://www.saudia-online.com/conversion%20Table.htm
Ending velocity of bag= 8.45 meters/s
http://tutor4physics.com/calculators.htm
KE= ½(45.36)(8.45)(8.45) = 1619 joules
Convert 1619 Joules back to food/pounds force a.k.a. weight = 598
http://www.cleavebooks.co.uk/scol/ccenrgy.htm
For the controlled demolition theory to be correct the guy’s head must be able to apply almost 598 foot/pounds of force to stop the bag after such a fall.
Is this reasonable? I think we can safely, and without the possibility of jail time for seriously injuring some poor test subject, conclude that it is not.
Maybe “Galileo” would like to put this theory’s primary assumption to the test with a 100 bag of bull ?
The original Galileo was actually instrumental in noting that the rate of falling objects is not dependant on mass
http://www-istp.gsfc.nasa.gov/stargaze/Smass.htm . Perhaps our modern, more re ed, version of the real scientist can contribute something to science and prove that his head can hold, even for a split second, an eleven hundred pound object.
Dan, or anyone else, please feel free to recheck my calculations here. I might have deliberately made a mistake just to see if you are really following along…
