This is physics, listen up. This will probably be the last time I put this much effort into explaining something in an ATS post that should be
learned in a classroom.
Gravity is a force that tends to pull objects on Earth towards the center of the Earth. It is a relatively weak force.
Electromagnetism is the force that keeps objects from falling through each other, because the empty physical spaces between atoms and parts of atoms
and etc. is actually vast. This force is
much stronger than gravity.
One of the laws of thermodynamics states that things will follow the path of least resistance, always.
A vector is a 2-dimensional number that has both a magnitude and a direction. For example, gravity will "pull" an object and cause it to accelerate
towards the center of the Earth at 9.8 meters per second per second (or meters per second squared). The magnitude is 9.8m/s^2 and the direction would
be -90 degrees whereas 0 degrees is perfectly horizontal, the x-axis.
I'm not familiar with what the forces associated with electromagnetism in dynamic systems are called, but in static systems they're called
normals, and the
normal force is the equal and opposite force "pushing up" on an object to counter-act gravity. Loads can be
increased and the normal will change proportionately to keep counter-acting gravity to prevent objects from falling into themselves up until a certain
point, but remember that the path of least resistance will still always be taken.
A simple mathematical model of WTC7 collapsing due to
asymmetrical damage centering around the South face would have gravity accelerating mass
into the path of least resistance (compromised columns towards the South end of the building).
For the sake of argument, let's say the entire base of the Southern facade is compromised.
Now we reach common sense, reaching back to our days as toddlers, stacking blocks upon each other and learning how they interact with each other in
different configurations.
Which way is that thing going to go, following the path of least resistance to the ground? Is the whole thing going to fall straight down at once, or
is gravity going to find a way to accelerate
half of the building more easily than the other, leading to the building
leaning?
A technical analysis here could get quite involved, with forces conflicting with each other at lots of angles and therefore sines and cosines and all
kinds of mess like this for each and every column being acted laterally on the North side of the building as the South side would be
trying to
fall down due to gravity, but would be offset by resistance, friction, electromagnetism, the normal force, or whatever you'd like to call it.
Point is, gravity wouldn't take over as if it's top dog. The building would have to fall at an angle into the direction of least resistance
(compromised structure) because of friction.
Another common sense example: kick a leg out from under a chair. The chair is going to fall in the direction of the missing leg. Why? Nothing is
preventing gravity from acting on that corner of the chair anymore, but the other legs are still preventing the chair from falling straight down.
Someone please tell me they understand this logic!
You guys understand this, right? It really shouldn't be debatable should it? The only way around this is to find some excuse for the loads to have
been transferred in some amazingly balanced way by the actual structure of the building, which is what NIST has been trying to come up with for the
past 5 years.
Btw, "leaning" in all four directions (WTC7 damaged buildings on all sides and leaned into Vesey Street to the South) is more indicative of an
explosive collapse to me, rather than some sly way of weaseling out of how straight the building came down, because the centers of gravity in those
four cardinal directions are all going to cancel each other out and put the greater center of gravity
right back into the footprint.
WTC7
fell into its footprint, not that a 2-second glance at any photo wouldn't tell you this basic info anyway, seeing as how the biggest pile is
right at the base of where WTC7 once stood. Common freaking sense people.
[edit on 17-2-2007 by bsbray11]