A 9/11 physics question

I have recently encountered a co-worker who believes that the September 11, 2001 attacks were a government conspiracy. While this is not unique, one point that he brought up was that the buildings fell straight down, and were not influenced by the winds that day in New York City.

My answer to this question was that gravity as a force probably overrode the force of the wind in question.

Without spending too much time on the conspiracy itself, I was wondering if anyone knows a (the) mathematical formula to this equation. I can estimate the weight if needed from the 9/11 commission report, but I would like to figure what level of wind would have been needed in order to significantly impact the falling trajectory of the towers.

The reason they fell was because the metal supports melted, so it would fall straight down wouldn't it?DrSponge

At most the winds at that height would be 70 mph and that's overestimating. They're not going to do anything to a building weighing hundreds of tons.

The reason they fell was because the metal supports melted, so it would fall straight down wouldn't it?DrSponge

Well, I have never heard the wind theory, and it doesn't make much sense as to why the wind would affect the buildings more so if it was because of the plane crashing in the towers causing them to collapse, than it being a controlled demolition.

If the wind was supposed to be strong enough make the building fall at more of an angle the building would have to be insanely light.

He does realize that wind also affects controlled demolitions, right?

Anyways, the building is just way too heavy, and gravity too strong. There was likely some horizontal movement due to wind, but it had to be very small.

I am not a physics expert, nor am I an expert on building design and tolerances, so I really don't have any opinion on the towers (and building 7) falling. But one thing strikes me as odd...many people claim the "truthers" are crazy and say that they fell due to fire and it's no mystery. The thing that strikes me as odd is that many sky scrapers have had fires, many much worse, and yet NONE of them collapsed. http://911research.wtc7.net/wtc/analysis/compare/fires.html Just look at the bottom example (Bejing)...completely engulfed in flames for over 3 hours...and still didn't fall. But again, I am no expert so I refuse to draw any conclusions. dnuggs40

How many of those had trans-Atlantic airplanes full of jet fuel crashed into them?foxhound_fox

There were no planes! That's just what the government WANTS you to think! :P

I am not a physics expert, nor am I an expert on building design and tolerances, so I really don't have any opinion on the towers (and building 7) falling. But one thing strikes me as odd...many people claim the "truthers" are crazy and say that they fell due to fire and it's no mystery. The thing that strikes me as odd is that many sky scrapers have had fires, many much worse, and yet NONE of them collapsed. http://911research.wtc7.net/wtc/analysis/compare/fires.html Just look at the bottom example (Bejing)...completely engulfed in flames for over 3 hours...and still didn't fall. But again, I am no expert so I refuse to draw any conclusions. dnuggs40

True, but they don't even mention the force that a plane travelling at maximum speed with a full fuel tank creates. That's what makes 9/11 unique.

[QUOTE="dnuggs40"]I am not a physics expert, nor am I an expert on building design and tolerances, so I really don't have any opinion on the towers (and building 7) falling. But one thing strikes me as odd...many people claim the "truthers" are crazy and say that they fell due to fire and it's no mystery. The thing that strikes me as odd is that many sky scrapers have had fires, many much worse, and yet NONE of them collapsed. http://911research.wtc7.net/wtc/analysis/compare/fires.html Just look at the bottom example (Bejing)...completely engulfed in flames for over 3 hours...and still didn't fall. But again, I am no expert so I refuse to draw any conclusions. foxhound_fox

Looking at the aftermath pictures for the bejing tower you can see the structural damage from a raging inferno going on for hours was tremendous.

Also, the empire state building was hit by a plane, and burned for hours, yet never collapsed. I realize it was a smaller plane, but the building was also much older.

Again, I don't claim to know what happened, but it worries me and I think at best it shows that these buildings had severe design problems, and makes me wonder about other buildings in NY.

A more interesting question would be, if it is possible for a building like that to collapse the way it did, without a controlled demolition.

Sure the structure of the towers where the planes hit would collapse due to the heat (although mathematical calculations states otherwise, but that is another thread), but the structure beneath the affected area remained unaffected, partly or fully, depending on how far the fire managed to spread. Then how is it possible for the buildings to have collapsed in that fashion, when clearly the building itself would have caused tremendous friction, yet it falls down at near 9 m/sec?

If you'd ask someone for a demolition of a skyscraper, but only using explosives at the top floors, he would just give you a wierd look.

[QUOTE="foxhound_fox"][QUOTE="dnuggs40"]I am not a physics expert, nor am I an expert on building design and tolerances, so I really don't have any opinion on the towers (and building 7) falling. But one thing strikes me as odd...many people claim the "truthers" are crazy and say that they fell due to fire and it's no mystery. The thing that strikes me as odd is that many sky scrapers have had fires, many much worse, and yet NONE of them collapsed. http://911research.wtc7.net/wtc/analysis/compare/fires.html Just look at the bottom example (Bejing)...completely engulfed in flames for over 3 hours...and still didn't fall. But again, I am no expert so I refuse to draw any conclusions. dnuggs40

Yes, and jet fuel burns at very low tempratures compared to wood and whatnot, so that argument falls short either way.

They didn't fall because of the impact though, the 9/11 commission said the fires was what caused the steel to weaken and hence collapse. The temps in both (even without jet fuel) were similar. dnuggs40

[QUOTE="dnuggs40"]They didn't fall because of the impact though, the 9/11 commission said the fires was what caused the steel to weaken and hence collapse. The temps in both (even without jet fuel) were similar. foxhound_fox

He never said he knew for sure that it was a government conspiracy, he never said he had definitive proof of it being conspiracy. Clearly an intelligent being like yourself wouldn't make such assumptions just to put fuel on the fire?

I do physics but im not the best, I cant even remember what the question was

Some vector resolution is needed. You'll need to find the wind velocity and the mass of the building above the point of impact

The wind, on a vector diagram will probably be on a tiny gradient of effect against the velocity gained by the accelerating mass of the top of the building. This force obtained by the accelerating mass will also be a greater force than the foundations of the floor below can withstand and so you get that rippling effect as the mass builds up..

A stab in the dark really.

[QUOTE="dnuggs40"]They didn't fall because of the impact though, the 9/11 commission said the fires was what caused the steel to weaken and hence collapse. The temps in both (even without jet fuel) were similar. foxhound_fox

I would like to figure what level of wind would have been needed in order to significantly impact the falling trajectory of the towers.Chemistian

[QUOTE="Chemistian"]I would like to figure what level of wind would have been needed in order to significantly impact the falling trajectory of the towers.Funky_Llama

[QUOTE="foxhound_fox"][QUOTE="dnuggs40"]I am not a physics expert, nor am I an expert on building design and tolerances, so I really don't have any opinion on the towers (and building 7) falling. But one thing strikes me as odd...many people claim the "truthers" are crazy and say that they fell due to fire and it's no mystery. The thing that strikes me as odd is that many sky scrapers have had fires, many much worse, and yet NONE of them collapsed. http://911research.wtc7.net/wtc/analysis/compare/fires.html Just look at the bottom example (Bejing)...completely engulfed in flames for over 3 hours...and still didn't fall. But again, I am no expert so I refuse to draw any conclusions. dnuggs40

Looking at the aftermath pictures for the bejing tower you can see the structural damage from a raging inferno going on for hours was tremendous.

Also, the empire state building was hit by a plane, and burned for hours, yet never collapsed. I realize it was a smaller plane, but the building was also much older.

Again, I don't claim to know what happened, but it worries me and I think at best it shows that these buildings had severe design problems, and makes me wonder about other buildings in NY.

Pretty Interesting video I found on the subject.

http://www.youtube.com/watch?v=B72pzadCICE&feature=subscriptionEVOLV3

Took me a while but i think i've found a way to work out the potential energy needed to move the tower. By rearranging one of the suvat equations we need to work out the final velocity of the tower falling, then substitude that into the kinetic energy equation, and since potential energy lossed is equal to kinetic gained that should be your answer...i think :D

The equation should be this K.E = 1/2m((1/2a(t^2)+s)/t)^2

where K.E = kinteic energy, m = mass, a = acceleration of the falling tower, t = time taken for the tower to fully collapse, s = displacement of the top of the tower to where it hits the ground (which will be the hypontenuse of a right-angled triangle since your saying the wind effects the tower in the first place, just the pythagoras equation to work that out)

Once you have the kinetic energy it's equal to the potential energy ;)

so aparently, the US government has the ability to defy wind if the conspiracy theory is accurate. That's not even logical.

That's like saying "wow, that apple fell out of the tree and wasnt affected by wind. it must've been the government!"

there's no connection at all. tell your coworker he's stupid.

They didn't fall because of the impact though, the 9/11 commission said the fires was what caused the steel to weaken and hence collapse. The temps in both (even without jet fuel) were similar.

Looking at the aftermath pictures for the bejing tower you can see the structural damage from a raging inferno going on for hours was tremendous.

Also, the empire state building was hit by a plane, and burned for hours, yet never collapsed. I realize it was a smaller plane, but the building was also much older.

Again, I don't claim to know what happened, but it worries me and I think at best it shows that these buildings had severe design problems, and makes me wonder about other buildings in NY.

dnuggs40

[QUOTE="dnuggs40"]

[QUOTE="foxhound_fox"]
How many of those had trans-Atlantic airplanes full of jet fuel crashed into them?Ontain

Looking at the aftermath pictures for the bejing tower you can see the structural damage from a raging inferno going on for hours was tremendous.

Also, the empire state building was hit by a plane, and burned for hours, yet never collapsed. I realize it was a smaller plane, but the building was also much older.

Again, I don't claim to know what happened, but it worries me and I think at best it shows that these buildings had severe design problems, and makes me wonder about other buildings in NY.

Jet fuel does NOT burn hotter than normal fires, in fact, quite the opposite. Jet fuel actually burns at pretty low temperatures, beneath 300 degrees Celsius

I just found a pretty interesting video regarding 9/11, that is much better than the usual the plane were missiles!!!11!1!!1!! videos.

http://www.youtube.com/watch?v=qW81Cd7nNH8&feature=related

Speaking as someone who was standing on the street only blocks from the WTC when a plane hit the second tower, in the past I got extremely annoyed by a number of 9/11 conspiracy sites on youtube (especially those asserting that "there were no planes," "the towers never fell it's all a hologram," "nobody died at the WTC" and "if you say you saw a plane hit the WTC you are a governement shill") and couldn't help attempting to debate them and say what I knew personally. Of course, I never got anywhere because people tend to cling desperately to conspiracy theories, especially if they've carved out their own little sub division (ex. holograms) because it becomes almost their entire identity and what makes them superior (notice how often they'll tell people to "wake up" and other dismissive condescending bs that is conveniently self aggrandizing) to all of us "sheep." They claim to be skeptical of official explanations (which I whole heartedly agree with) but completely lose any ability to be skeptical when it comes to their own assertions, which should be just as much of a red flag as the inconsistencies they point to as being proof.

I never do this, but I would direct this person to this site, which is a very methodical, rational and clear collection of articles debunking various 9/11 conspiracy theories. It also specifically deals with the tower collapse.

http://www.debunking911.com

The steel was never fireproofed, the company who was supposed to fireproof the steel supports never actually did it so that affected the melting / weakening of the steel beamsp2rus

Of course it was fireproofed, the building would have never passed inspection without having fp material. The problem is that they applied it by spraying it on, so it didn't adhere properly. It came off when the plane hit the building and the steel became exposed. Once its exposed, it doesn't need to melt in order to fail (didn't get that hot), it did however get hot enough to lose its rigidity, and once that happens it becomes pliable, which causes it to fail.

Jet Fuel burns at about half the temp that's needed to melt steel. The sad thing is steel loses half it's strengh around the temp that jet fuel burns at. Hence, building falls down.

If there was a controlled detonation on lower floors. It would have been visible due to how much explosives you'd need to bring that building down.

Even hurricane winds only slightly sway the buildings. We'd have to be talking about those super massive storms that are on Jupiter that are the size of Earth, and have 400km/h wind speeds for it to have any effect.DigitalExile

I kinda agree with you except for on thing. If a strong enough Tornado hit that building. it would be gone. So, I'm just saying we have a storm on earth that could take it down!

Law of Conservation of Momentum. The wind doesn't have enough mass to even budge the building.unholymight

Basically this, which is why physicists don't consider air resistance when working out motion projectiles and all that lark.