first of all, that snopes thing is bull. aluminum can't "burn up". the most it can do is melt. aluminum would have to reach a temperature of about 2700 degrees fahrenheit to "burn up". 2700 degrees fahrenheit is the approximate boiling point of aluminum. boiling point is the temperature in which a liquid turns to a gas. so to burn up, or not be seen it would have to turn to a gas. if only melted, aluminum would become solid again and clearly visible shortly after. the fires would be making the metal too hot. it would have to be cleaned up in buckets, and u'd still see lots of glowing red melted aluminum on the lawn. there is none. and once the fires go out... the aluminum will become solid again.
They only had to be hot enough to cause the trusses between the floors to collapse. Heated metal weakens, but the metal doesn't have to melt to break down.
weeken it yes... but you must remember... buildings are built to be MUCH stronger than they need to be. it's a rule of artichitecture. now first of all... like hdog said, the fuel for the most part burnt up immediately. after the fuel is gone, ur left with fires of about 500 degrees fahrenheit... that's NOTHING to steel. steel could take that like a kevlar vest takes a tiny .22 derenger... now even IF it was possible to collapse like that... you'd FIRST noticably see the building start to buckle...
now historical example: 1992 (i think) there was a building fire in philadlphia, EIGHT floors were COMPLETELY on fire... raging in flames... it did not collapse after hours and hours of being on fire. it was a building similar to the size of WTC 7.
[/QUOTE]Wrong again. Only one floor has to collapse. The mass of the floors above the collapsed floor acts as a ram to the floor beneath the collapsed floor, which rams the floor beneath that, and so on, adding mass and energy as it falls. High school physics, my friend: F=ma.[/QUOTE]
first of all, you're using the wrong law. quiz for you: what has more force, an 11 lb. piece of steel resting on the ground, or a 10 lb. piece of metal that's been falling for 5 seconds and has reached a velocity of 49 m/s?
if you guessed the falling piece of metal at 49 m/s, you're wrong. F = ma. a = 9.8 whether ur falling or sitting still. it's called ur weight. i weigh 115 lbs. whether im sitting still or skydiving, falling thru the air.
now, to talk about MOMENTUM, which is what u meant to speak of. momentum = m*v. but after falling a mere 10 ft, an object will only be traveling 17.3 MPH. that's not very fast. HIGH SCHOOL PHYSICS, MY FRIEND. that momentum, when hit the floor below will get distributed throughout the tower. now only the floor that collapses will collapse... the ones above it dont... according to the pancake theory... thats ONE floor hitting a floor below it. the energy of the falling floor will get distributed THROUGHOUT all the lower floors... dont forget u have about 80 floors below to distribute the energy too... and dont forget the structure of the towers... the support columns START at the bottom at a thickness of 2"... then taper away to 1/4 inch at the top... that's a LOT of steel on those lower 80 floors to get the energy distributed to. HIGH SCHOOL PHYSICS, MY FRIEND.
Remember that when we watch the controlled destructions of buildings on TV (or, if you're lucky enough, in real life), the charges that collapse the buildings are relatively small. The mass of the building and the height from which the buildings fall creates enough energy to demolish the structure.
what you state here is correct. the charges are small. but the explosives create enough heat to melt steel. explosives create temperatures of about 3000 degrees fahrenheit. steel's melting point can be estimated at 2850 degrees fahrenheit. you also have to remember, MOST controlled demolitions set a charge at nearly every joint. that's because it's designed to blow out floor by floor, making it so all the steel gets broken up into small pieces, and the building falls into its footprint. the towers fell into their footprints.
Yours truly,
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