insane_alien

http://en.wikipedia.org/wiki/White_gold you need to learn how to search the web

yes they can. http://en.wikipedia.org/wiki/Water_jet_cutter <should tell you all you need to know

no 81% is wrong. there is no such thing as freefall speed. you don't just start falling at a constant speed. it is an acceleration and must be described in terms of acceleration. that means it fell at 70% of freefall acceleration. i had thought that you knew the difference which is why i used your convention several times. but now it is obvious that you don't get it. and 70% of freefall seems a reasonable acceleration for a collapsing building. buildings do consist mostly of empty space. please, consult wikipedia or a basic physics textbook before you comment on that again. and stop saying it was near freefall, it wasn't viscosity is a property of fluids. not solids. yeah, not all skyscrapers will experience conditions as extreme as these. also, conventional skyscrapers are build differently from the towers so they can't really be compared.(would you compare an ocean liner with a rowboat?) And yes, i do suggest the guys data would be irrelevant, if he wasn't at the hottest part of the fire where the collapse occured then he would not know the circumstances of collapse. the conditions below and above this point would not matter as these were not the points of collapse

I have a big problem with the controlled demolition hypothesis. the problem is this. on the towers we seen the collapse start aroung the area where the planes hit an the fires had been burning for a few hours. now, this may sound completely crazy but, how the hell did the explosives survive? explosives are not the most stable of chemicals. there are 3 possibilities i can see. 1/ the explosives would have detonated on impact bringing the towers down immediately and it would be very obvious explosives were used since the building should have withstood the initial impact. 2/ the explosives would have self detonated after a few minutes and it would still be obvious that they were used. 3/ the explosives would have partially burnt away and the detonation of the remaining would be sparse and uneven. would cause with very uneven collapse or fail to bring the towers down. personally, i think a combination of 1/ and 2/ would happen. explosives don't like to hang around. you explain to me how they survived that long and performed so well. Just a note on the video: if it was a red hot oven in there, then there are a number of things that could look like molten steel to the casual observer, glass is the most obvious one that springs to mind. there is even mention of it being like molten lava. now, last time i was working with molten steel, it was quite runny. lava, implies a viscous liquid. glass behaves this way. and anything in there would glow red from blackbody radiation. most people identify materials by the colour if they cannot touch it. now, as the only colour visile would be a bright red glow, this method of identification fails.

i think he means rigor mortis

if you read Isaac Asimov's 'The Last Question' it has a similar theme.

the failure modes are nearly identical the cracks propagate on their own all the energy required is enough for the initial displacement. i cannot address the energies involved with any great accuracy because i know neither the average size of the chunks, and mechanical properties of the floor. but a rough estimate would be easily covered by the 30% reduction in acceleration. also, i imagine the blocks of concrete themselves dropping would cause a good deal of pulverisation. it could be said that the onus is on you to provide evidence that the energy involved was not capable of causing the level of disintigration observed. please, point me to where i said it was weakened at -40*C i don't recal saying that. what was meant to be inferred from my statements since you don't seem to see it is that the conditions of the building below the point of collapse wouldn't have mattered much. they were infact in very good condition with nearly no damage at all. if they were weakened then it would have fell faster. please, don't put words in my mouth. i may be a student but it isn't drivel. thats an ad hominem attack. you see, the point is to attack the argument rather than the person giving it. no, there does need to be investigation because the planes were not the direct cause of collapse. the NIST was concerned with discovering the reasons that caused them to collapse. i'm sure that structural engineers, not associated with the NIST are looking into the collapse to find out what happened in there but that was not part of the NIST's inquiry which is why it would have been a waste of resources for the NIST to conduct it. nope not really. the cause of the failure, not how it did it

its in the mandate you quoted there causes, not effects. we know the effects. we seen them. all they had to do was get to the point where the building started to collapse and then the rest was inevitable. to model the collapse itself would have been superfluous, a waste of resources and outwith the scope of the inquiry. by the way, spivver, still waiting for reasons why my post was poppycock.

well, andromeda is hurtling towards us at a few hundered kilometers per second and we have a few smaller galaxies orbiting us and several sub-galaxies getting absorbed into the milkyway. theres a lot of motion but if you zoom out far enough it all kind of looks static.

i know its heisenbergs uncertainty principle. i was keeping in line with the quantum mechanical humour.

it wouldn't seperate completely. in a 1 litre container it can probably be viewed as a homogenous mixture.if it was a million litres then there would be some degree of separation. i don't think you would be able to get full separation unless there was sufficient pressure for the CO2 to solidify.

ping -c 4 www.mrelativity.net ping: unknown host www.mrelativity.net probably because that site doesn't exist. anyway, google page ranks can be artificially inflated by bots. perhaps that wa why. never heard of the theory. what journals has it been published in?

because their primary aim was to find out why it collapsed. we know how it collapsed. we seen it. because we have already seen what happened. we don't really need a model of it. this was not the primary aim in any case. to do so would have been a waste of money.

torque is also Force times radius. try working with that.

well, what working have you done so far? we will help you answer the question but we don't just give out the answer to homework questions. you'll need the formulae for angular acceleration and torque.

Analogy

i've never seen a ball expand when its falling. if anything, it would shrink and increase in internal pressure because of the increasing external pressure. it would also heat up due to friction with the air. sounds like you need to work on it some more. S/T/E\P/ is no longer a pretty pattern.

a couple of 10's of thousands of lbs. though the biggest difference was the impact velocity. that would have thron the energy of impact up immensely.

there a number of reasons why the could still be standing, they are the strongest parts of the building and they are at ground level. this means the debris would not have the chance to knock them about as much. also, they never fell any distance. its the same principle as how a long straw is easy to bend if you push in on both ends but with a short straw its much harder. anything else?

they pulverised into chunks and dust. i see you have provided an extremely indepth response as to why my posts were poppycock. but, i feel that for some strange reason unbeknown to me that you have not really proven me wrong.

fine i chose my wording badly. the jets had just taken off not that long ago. they had enough fuel for the trip they were undertaking. they were also considerably bigger than the 707-300's the towers were designed to withstand and they were travelling faster than the 180mph factored into the design.

well, i'm no quincey.

no they are not the same. the brain is still alive in a coma patient(thats why you can come out of a coma). you can be in a coma for years there is no limit other than your lifespan. a person is clinically dead when their heart stops but isn't actually dead till their brain stops. IIRC

okay, take a thin(-ish) plate of glass or ceramic and some thick working gloves. put the plate on two separated bricks. take your hand and apply a force. try to see how far you have to move it before it shatters. the same principle applies as concrete can shatter like glass, it has a greater leeway before it will shatter but its still quite small. once it starts to shatter it then doesn't need much energy input. and, just because a workman has to use a pneumatic drill since it would be hopeless to try a constant force approach with out sending him skyward which then involves a lot of effort does not mean that its outwith the potential work of a building collapsing. you can't compare the two scenarios, different type of force, different scale of force, different scale. infact the only thing the same is that concrete gets broke. i've proven that even using the times YOU gave for collapse they fell nowhere near freefall acceleration. 70% of freefall acceleration is NOT NEAR freefall. stop stating this as fact its been proven wrong. the 30% reduction in acceleration went towards pulverization and resistance from the standing structure. no, it relies on the fact that the bottom part disintegrates WHEN the top part of the building hits it. it really doesn't matter what happened to it before (nothing). they only needed to remain reasonably intact for the first drop of a couple of floors then they only need to stay roughly as a concentrated mass. they could even behave like a viscous liquid and it would still work(thats actually what happened, you see debris flowing over the side). yes, it would, could and did. though, it doesn't dissipate nearly as much energy as you seem to imagine it did. i have shown why. well, seeing as the mass didn't just disappear when the floors disintegrated it actually gained mass. that would cause it to disintegrate the floor below even easier and gain more mass, and go through the floor below even easier and gain more mass and... till it hits the ground. of course, there is the fact that debris spilled over the side, this would imply that it would reach a equilibrium mass and reach a terminal velocity. it might even get stopped. although, we do not have a 10000 story building to test it on. and even if we did we wouldn't be alllowed to test it. why would it make it nonsense? its perfect conditions for pancaking to occur. the potential energy, although finitite, was enough. if you want to be pernickity then this potential energy was put into the towers by the cranes that lifted the material up. chemical energy from fires likely. could potentially have been shock heating as well. well it does use a number of logical fallacies and factual inaccuracies. also, when translating science to laymens terms there is something lost in the translation. when you get to a certain level of science (like fracture mechanics for instance) you need to have a certain level of knowledge before hand for you to actually understand what happens. without this knowledge you can think you understand it, chances are you got it wrong. ? go ahead not that it makes a blind bit of difference, he wasn't up at the heart of the fire now was he. don't care what temp it was at the bottom. could have been a chilly -40*C and it wouldn't have mattered

you'll probably have a higher concentration of CO2 at the bottom and H2 at the top but they won't fully separate. it'll be roughly even i would imagine since its a small container.