Gravity Can't Do This!

Originally posted by WarminIndy
We can say that the amount of empty space between the the floors would not buffer a load greater than the weight of the air. But that air in the spaces was sucked up toward the massive fire, leaving those empty spaces as a vacuum.

Seriously?

You want us to believe that there was a vacuum between the floors?

Really?

Wow...

Originally posted by tezzajw

Originally posted by WarminIndy
We can say that the amount of empty space between the the floors would not buffer a load greater than the weight of the air. But that air in the spaces was sucked up toward the massive fire, leaving those empty spaces as a vacuum.

Seriously?

You want us to believe that there was a vacuum between the floors?

Really?

Wow...

What creates a vacuum? The absence of air. Why causes air to move out? The need to fuel. What happens in a vacuum? The velocity of objects increase no matter the weight.

Have you ever seen the experiment in school with a vacuum tube? A tin ball and feather fall at the same speed.

Originally posted by WarminIndy
What creates a vacuum? The absence of air. Why causes air to move out? The need to fuel. What happens in a vacuum?

So you still want us to believe that there was a vacuum between the floors???

Really???

Double wow...

Originally posted by wmd_2008
reply to post by ANOK

 

With the start of the collaspe of the N Tower you had the equivalent of 15 floors of mass dropping one floor (around 12ft) that hit the floor below which failed.

Again you are mistaken, you are ignoring all the mass of the lower structure.

I have explained this to you before, IF the top section was all falling as one block of floors connected together, then you have to realise that the bottom section is also a block of floors all connected together. You have to either consider it two blocks of floors impacting, or two floors impacting, not one block of floors impacting one floor. You start off with an incorrect premiss.

If you think of it correctly, as a block of 15 floors falling on a block of 95 floors, then you will realise your conclusions are incorrect.

You now have 16 floors of falling mass which guess what can now drop a floor (around 12 ft) now if the first floor couldn't survive 15 floors what make you think the next would survive 16 floors worth of mass.

If you actually address the equal opposite reaction laws you would realise that the floor that is dropping will also be damaged, both floors would be damaged on impact. IF you are right and the dropping floor puts more force on the impacted floor (it wouldn't), the dropping floor would still receive some damage. Let's say for sake of argument the impacted floors receive twice the damage of the dropping floors (that is being very generous), 15 floors dropping on 95, you would still have 65 undamaged floors. To get 15 floors to destroy 95 floors would mean the top would have to have about seven times the mass of the bottom. When in fact the building had more mass at the bottom than the top.

All the floors had the same connections all the way to the bottom, the floor connections could only support there mass x the safety factor.

Again I have explained why the connections are irrelevant to the resistance of stacking up floors.

I spoke to an engineer today regarding this he said that the impact of a falling mass will generate twice repeat twice its static load and that is used as a minimum.

Really? Who was that, PLB? Once again equal opposite reaction law, the force of the load will be the same on both the impacting floors. Your engineer either neglected to explain that, or you asked a fake engineer like PLB.

BTW I find it amusing that you have to make a claim like this to try to bolster your claims, while the rest of us just simply provide factual sources. You must be as dumb as you think we are.

He said the actual impact force would be a lot more but you need to know either how quick the floor fails or the distance the impacting load travels before the impacted floor fails.

Well obviously to know the forces you would need those figures. But again the forces could be that of an atomic bomb, but equal opposite reaction would still apply, and both impacting objects would feel the same force. The only thing that really makes the difference is the mass of the objects.

How many time do I have to post this until it sinks in?...

The size of the forces on the first object equals the size of the force on the second object.

www.physicsclassroom.com...

Also due to the design the walls loose stability once floors are lost. What myself and others on here have been telling you for ages.

You have been telling me nothing but your uneducated opinions with no facts, or sources, to support your claims.
You can't even explain how the floors failed in the first place let alone how that could lead to complete collapse through the path of increasing most resistance. You just keep repeating the same fallacies.

You keep looking at the literal meanings of words NO one has claimed that the falling floors all stay in one piece or all fall perfectly horizontally thats why we say mass of the falling floors etc.

Huh? For your pancake collapse to have happened floors would have had to at least 'stay in one piece'. You already want to think a smaller mass can crush a larger mass, and yet don't realise that if floors are being crushed then you are losing mass every time a floors is crushed. So you are losing mass, and Ke, yet you still think your 15 floors can crush 95 floors?

The first impact would have been the equivalent of 30+ floors minimum for the north tower and 60+ floors for the south tower.

And again the forces pushing back on those floors would be the same, equal opposite reaction. But where are you getting those figures? The impact was at the 95th floor, so that is 15 not 30 floors falling. But regardless if you want to claim 30, then you have 30 falling on 80, you still have less mass falling on more mass.

Once again you did not answer my question about the bug hitting the windshield, and you have not addressed the laws of motion once in your reply. Why is that?

Originally posted by WarminIndy
The velocity of objects increase no matter the weight.

You guys must be all getting this from the same source, because you are all making the same mistake in your understanding.

Velocity increases the force on BOTH objects, not just the one being impacted. Equal and opposite reaction.

Originally posted by ANOK

Originally posted by WarminIndy
The velocity of objects increase no matter the weight.

You guys must be all getting this from the same source, because you are all making the same mistake in your understanding.

Velocity increases the force on BOTH objects, not just the one being impacted. Equal and opposite reaction.

Again, did you not read about what happens in a vacuum? Why don't you go to any 9th grade General Science teacher and ask them to show you the vacuum tube experiment.

A feather and a ball falls at the same rate of speed, regardless of the mass of each individual object.

www.exploratorium.edu...

When a vacuum is created...and it is what happens when you do the egg in a bottle experiment, the bottle is heated and the egg is sucked into the smaller opening. But if you were to take a can and suck the air out of it (create a vacuum), an implosion occurs.


How powerful is the explosion comparable to the force of gravity? In order to get an answer, I'll take the limit of a very powerful explosion symmetrically scattering lots of very lot particles. Furthermore, lets take the initial shape to be a spherical shell of some radius R. Now, the total mass in our system is constant (in the non-relativistic limit). So, we expect as the shell moves outward that:
4*pi*r^2 *S= M
or
S = M/(4*pi*r^2). Here, M is the total mass, r is the current radius of the shell. S is the mass/area (This was done as an experiment on exploding shells).

And according to firemen, a vacuum can indeed be created by fire...

www.workingfire.net...

So the airplanes were the initial cause of the fire that resulted in progressive steps of a domino effect.

reply to post by wmd_2008

SORRY BUT YOU ARE WRONG.

Sorry guy, but do you actually want to point out a single thing in my post which is wrong? I understand that you are emotional after having your entire post picked apart and errors shown by several members but that is no reason to just yell back that I am wrong.

The impact load would be considered as a MINIMUM of twice the static load of the falling mass it wouldn't be less but it could and probably would be way more than twice the static load depending on time taken for the slab to fail which he had no doubt would and did.

I've never speculated on what the load would be, so I can't be wrong there...

So for the North Tower that's the equivalent of 30 floors minimum and for the South Tower 60 floors minimum.

I'm aware of the size of the top sections.

the only thing that can resist the imposed load is the connections as the floors are suspended between the walls and core.

If that were true the only structural failures we would see during collapse would have been these floor connections (and ductile column failure once they achieved very long unrestrained lengths). Obviously there was a lot more structure being destroyed during collapse than that (as seen on every camera angle). Entire floor slabs were not slotting perfectly between internal and external columns at a perfectly flat angle. There was some offset and some angle that the top section fell at relative to the bottom, meaning floor slabs would have been loading columns also. It also takes a good amount of energy to crush a truss..

He also commented on how the stability of the walls would be affected by the loss of the floor and impact from debris falling as well.

As did I, in my previous post.

This engineer was a senior engineer for one of the biggest firms in the UK and now earns his living as an independent engineering consultant.

Very impressive.

Looking forward to your reply.

I'm still looking forward to your reply to my previous post. You failed to address any of the points I made (I mean come on, your lack of understanding for simple Newtonian physics got called out). If you think that the towers were exempt from equal and opposite reactions because the impact forces were too "massive" then it's no wonder the OS sounds completely plausible to you. Just don't expect people to give you much credibility.

Originally posted by WarminIndy

Again, did you not read about what happens in a vacuum? Why don't you go to any 9th grade General Science teacher and ask them to show you the vacuum tube experiment.

So the airplanes were the initial cause of the fire that resulted in progressive steps of a domino effect.

What has what happens in a vacuum got to do with the discussion? Is this another new OSer made up excuse for something?

Airplanes had nothing to do with the actual collapse, and neither did the fires. You can argue they initiated the collapse, but they did not effect the mass of the structure bellow where the fires were during the actual collapse.

The laws of motion are still relevant, no matter what caused the collapse, or it's initiation. Please address the equal opposite reaction, and conservation of momentum laws, otherwise your claims are based on nothing but personal opinion and assumptions.

reply to post by WarminIndy

the walls are too weak to withstand the weight of the mass of fire

Gold.

What creates a vacuum? The absence of air. Why causes air to move out? The need to fuel. What happens in a vacuum? The velocity of objects increase no matter the weight.

I guess all those ejections that some people call squibs were definitely not caused by compressed air then, right?

reply to post by WarminIndy

Ok...imagery again.

I sincerely hope you are not being serious.

reply to post by tezzajw

samkent, it appears that remedial physics lessons are probably needed to help your misunderstanding here.

Try this experiment:
Take a set of scales into a stationary elevator. Stand on them and record your weight.
Now, while the elevator is accelerating, moving upwards, stand on the scales and record your weight.
Finally, while the elevator is decelerating, moving upwards, stand on the scales and record your weight.

Try this on for size.
Assume you live on the 9th floor of a 10 story apartment building.
You have no furniture and sleep on the floor.
Each week you ge to the grocery store and buy cans of corn.
You stack the corn week after week, month after month.
Will the floor give way at some point? Yes or no.

If you answer is yes answer the next question.
What will happen to the 8th floor when the contents of the 9th floor hits it?

reply to post by samkent

Originally posted by samkent
Each week you ge to the grocery store and buy cans of corn.
You stack the corn week after week, month after month.

samkent, you have not explained your claim that on Earth mass = weight.

Please explain how this is true or revise it or retract it.

In beginner science classes, you might learn that mass is a scalar quantity that's measured in kilograms (SI units). Weight is a vector quantity that's measured in newtons (SI units).

You keep on stacking your corn cans, but that's not going to help you explain why you believe that mass = weight.

"Jimmy crack corn and I don't care."
samkent stack corn and I don't care.

reply to post by ANOK

You guys must be all getting this from the same source, because you are all making the same mistake in your understanding.

Velocity increases the force on BOTH objects, not just the one being impacted. Equal and opposite reaction.

You keep going on about this when it makes no difference in this circumstance.
Ok so the falling floor gets pulverized by your equal and opposite reaction. It still has the same mass and that mass is now added to the floor below.
Or do you think the mass just disappears?
Someone, I don't remember if it was you stated that the mass was ejected. If that were the case how could the building fall "WITHIN IT'S OWN FOOTPRINT" as keeps being brought up?

Airplanes had nothing to do with the actual collapse, and neither did the fires. You can argue they initiated the collapse, but they did not effect the mass of the structure bellow where the fires were during the actual collapse.

The airplane added mass to the floor it rested on.

Answer this.
Do you think an undamaged floor can support..
It’s own weight + The weight of the floor above + The contents of the floor above?
Do you really think the floors could support unlimited weight? Or do you think that at some weight plus one pound the floor will give way?

reply to post by tezzajw

samkent, you have not explained your claim that on Earth mass = weight.

Please explain how this is true or revise it or retract it.

Here

It's from NYU the first link from Google.
And I quote..

If a cube has a mass of 90.91 kilograms and a weight of 200 pounds on Earth, what will its mass and weight be on another planet?

Please go to the page and check it out.

On Earth Mass and Weight are the same. If you weigh 150lbs you mass is 150lbs.
On the Moon your mass is still 150lbs but your weight drops to 25lbs.

Originally posted by samkent
On Earth Mass and Weight are the same. If you weigh 150lbs you mass is 150lbs.

I'll play along one more time, seeing you want to continue posting how ignorant you are of basic scientific principles...

When you stand in an elevator, on Earth, not a space elevator, or a moon elevator, can you please explain why your body feels heavier when the elevator accelerates upwards?

Hold a box of corn cans in your arms, and then tell me how heavy the box feels when the elevator is accelerating upwards.

Maybe one day you might figure it out, samkent...

reply to post by samkent

Someone, I don't remember if it was you stated that the mass was ejected. If that were the case how could the building fall "WITHIN IT'S OWN FOOTPRINT" as keeps being brought up?

[atsimg]http://files.abovetopsecret.com/images/member/85692fa545bf.jpg[/atsimg]
Tell me, samkent, what do you see here? [atsimg]http://files.abovetopsecret.com/images/member/15d7ad55641f.jpg[/atsimg] See that stuff that is no longer a part of the tower being ejected? It has mass, therefore mass was ejected.

The airplane added mass to the floor it rested on.

At the absolute maximum, a Boeing 767 weighs 450,000 lbs, or 225 tons. The twin towers weighed around 500,000 tons. Lets say the mass is distributed perfectly evenly among the 110 floors, that would give us 4545 tons of mass for each floor. Would an extra 225 tons really be the factor that causes the towers to collapse? Don't forget, 225 tons was the extremely generous estimate, that's assuming maximum fuel and passenger capacity. More realistically, it was probably around 100 tons.

Answer this.
Do you think an undamaged floor can support..
It’s own weight + The weight of the floor above + The contents of the floor above?

Yes....take a look at this image and answer a few questions: [atsimg]http://files.abovetopsecret.com/images/member/7f1b83509824.jpg[/atsimg] Are the floors underneath the red line supporting the weight of the floors above + the contents of the above floor?

Did you pass high school physics? After reading this in your previous post;

On Earth Mass and Weight are the same.

it really shows how truly limited your grasp of Physics is.

Weight, though related to mass, nonetheless differs from the latter. Weight essentially constitutes the force exerted on matter by the gravitational attraction of the Earth, and so it varies from place to place. In contrast, mass remains constant regardless of its location under ordinary circumstances.

You fail harder and harder everytime

Do you understand Newtons Third Law of Motion? Are the towers in that image in another dimension of space and time where the universally applicable laws of physics don't apply?

Originally posted by samkent
You keep going on about this when it makes no difference in this circumstance.

I have shown numerous times that the laws of motion apply to all objects and their movement. Stop being ignorant.

Ok so the falling floor gets pulverized by your equal and opposite reaction. It still has the same mass and that mass is now added to the floor below.

No, the fact that floors are being pulverized means Ke of the falling mass is being lost. Eventually you will get a build of floors, or rubble if it stayed inside the building, and it would stop collapsing. But you fail to take into account that there was no significant amount of the mass left inside the footprint of the building, so we can only logically surmise that the mass was ejected during the collapse. Which of course there is ample evidence of.
If mass is being ejected during the collapse you not only have a loss of Ke due to friction/resistance etc., but also loss of downward force from the loss of mass.

Someone, I don't remember if it was you stated that the mass was ejected. If that were the case how could the building fall "WITHIN IT'S OWN FOOTPRINT" as keeps being brought up?

Something else most of your OS supporters are confused about. WTC 7 fell in its own footprint, as evidence by all four outer walls visible on top of the rest of the collapsed building. The towers rubble was ejected in a 360d arc, as evidenced in photo's, and by FEMA. They were both vertical collapses through the resistance of their own structure, but they were not the same type of collapse. WTC 7 was a classic 'implosion demolition', the towers were too tall and thin for classic implosion demolition, not enough footprint for their height.

The airplane added mass to the floor it rested on.

Hardley. Do you know what the safety factor of the floors were? Do you know what pressure they were able to hold? Unless you do then you are just guessing. But regardless the weight was on what the 95th floor? If all the weight doing the crushing was provided by the plane on the 95th floor, then all the floors above that should have fell behind, but they didn't...



...they were already crushing themselves before the bottom started collapsing. Your whole premise is contradicted by what is actually happening when we look at the collapses.

Answer this.
Do you think an undamaged floor can support..
It’s own weight + The weight of the floor above + The contents of the floor above?
Do you really think the floors could support unlimited weight? Or do you think that at some weight plus one pound the floor will give way?

I've explained this, but you seem to not pay much attention. Floors could have been held up with toothpicks, and set on fire, the floors would still not crush themselves symmetrically and globally. Regardless what you are describing is not what happened, there was no build up of weight until it could take no more, it was an instant release of the floors. Unless you think 110 floors could all fail from a build up of weight in about 3 seconds?

reply to post by DrinkYourDrug


Haven't got time to go through all you post just now but what about you 1/3 static mass claim for the impact foce of the top section when it falls, I have now spoken to a few other real structural engineers who say it would be considered as a MINIMUM OF TWICE THE STATIC MASS but would mostl likely be much higher!

reply to post by wmd_2008


I don't doubt that. There is a difference between what they are saying and what I am saying, however.

There should have been large equal and opposite forces occurring at the collision of each floor. As F=ma, these large forces should have decelerated the falling mass.

But instead we have an average ~2/3rds free fall acceleration of the falling top section. The only way this massive acceleration can be achieved is if both the equal and opposite average crushing forces and average structural resistance forces were ~1/3rd of the static weight of the top section.

reply to post by DrinkYourDrug


Why should these forces have decelerated the mass? On what exactly do you base this?