The Obligatory 9/11 Thread Part II

[psikeyhackr]

skyscraper over 200 meters tall?

is „Argument of Big Scary Numbers“ a fallacy?
or is this just a case of „too bloody stupid to understand or memorize what has been explained about twice a year“ over the past decade?

It is certainly interesting that you think 200 meters might be a big scary number considering that it is half the height of the Twin Towers.

Claiming something twice a year is still never explaining anything. The supposed Potential Energy of the Twin Towers cannot be accurately computed without the distribution of mass data. Assuming the center of mass is at half the height of the building would imply that the structure could not be bottom heavy.

I covered that 10 years ago:

http://www.internationalskeptics.com/fo ... tcount=316

The JREF Retards said nothing back then.

psik

[Just A Theory]

Assuming the center of mass is at half the height of the building

Hell of an assumption there...

... and not even remotely close to a skyscraper (or any modern building really) is constructed.

[psikeyhackr]

Assuming the center of mass is at half the height of the building

Hell of an assumption there...

... and not even remotely close to a skyscraper (or any modern building really) is constructed.

[587607]
Tell Frank Greening.

[Xaihe]

skyscraper over 200 meters tall?

is „Argument of Big Scary Numbers“ a fallacy?
or is this just a case of „too bloody stupid to understand or memorize what has been explained about twice a year“ over the past decade?

It is certainly interesting that you think 200 meters might be a big scary number considering that it is half the height of the Twin Towers.

Claiming something twice a year is still never explaining anything. The supposed Potential Energy of the Twin Towers cannot be accurately computed without the distribution of mass data. Assuming the center of mass is at half the height of the building would imply that the structure could not be bottom heavy.

I covered that 10 years ago:

http://www.internationalskeptics.com/fo ... tcount=316

The JREF Retards said nothing back then.

psik

Can you explain again why knowing distribution of mass is at all important?

For example, if we assume the center of mass for the towers is at floor 10, then each floor is 11.1% heavier than the floor above it. The bottom floor would weight 37 thousand times the weight of the top floor and the total weight of the tower would be 373 thousand times the weight of the top floor. Even in this extreme example there would be no significant difference in the progressive collapse, assuming the construction is still according to the design of the twin towers. The reason for this is the nature of a progressive collapse.
By the way, in this example, assuming the bottom floor is solid steel, the top floor would have to be a tenth of the density of aerogel.

In conclusion, before you ask about the center of mass, first look at the collapse mechanism. Then you'll find that the center of mass can be just about anywhere and it wouldn't have any effect on the collapse.

[psikeyhackr]

Even in this extreme example there would be no significant difference in the progressive collapse, assuming the construction is still according to the design of the twin towers.

The mass distributions of steel and concrete would be different. The mass of both would affect the Conservation of Momentum calculations but the steel distribution would affect the strength of each LEVEL.

The lighter falling portion would have to overcome the strength of each LEVEL in addition to accelerating the mass.

http://www.internationalskeptics.com/fo ... tcount=316

The mass distribution changes the Potential Energy.

I have not tested that extreme on my python program:

http://breakfornews.com/forum/viewtopic.php?p=81888

But I have demonstrated that mass distribution does change collapse time. But my program does not take the strength of vertical supports needing to be broken in the collapse and affecting collapse time.

[Thommo]

But I have demonstrated that mass distribution does change collapse time.

Where? And by how much?

[psikeyhackr]

Where? And by how much?

I already supplied the link to the Python program. The fact that it changes with different mass distributions means it should be explained in relation to reality. Changing the steel distribution would change the distribution of strength in addition to the mass and my program ignores the strength factor.

[Thommo]

Do you mean the second link in #9485? And by how much does the collapse time change, depending on realistic variations?

[Xaihe]

Even in this extreme example there would be no significant difference in the progressive collapse, assuming the construction is still according to the design of the twin towers.

The mass distributions of steel and concrete would be different. The mass of both would affect the Conservation of Momentum calculations but the steel distribution would affect the strength of each LEVEL.

The lighter falling portion would have to overcome the strength of each LEVEL in addition to accelerating the mass.

http://www.internationalskeptics.com/fo ... tcount=316

The mass distribution changes the Potential Energy.

I have not tested that extreme on my python program:

http://breakfornews.com/forum/viewtopic.php?p=81888

But I have demonstrated that mass distribution does change collapse time. But my program does not take the strength of vertical supports needing to be broken in the collapse and affecting collapse time.

The strength of the supports did not actually play a role in the collapse, since the supports were essentially bypassed (stresed in ways they were not designed to handle). Given the design, those supports would have to have been many orders of magnitude stronger to slow down or even halt an ongoing collapse. So, the question still remains: how is the mass distribution relevant?

[psikeyhackr]

The strength of the supports did not actually play a role in the collapse, since the supports were essentially bypassed (stresed in ways they were not designed to handle). Given the design, those supports would have to have been many orders of magnitude stronger to slow down or even halt an ongoing collapse. So, the question still remains: how is the mass distribution relevant?

Bending supports or breaking joints would require energy. Since the only source would be the kinetic energy of the falling mass it would have to slow down to supply that energy. Let's see you build a physical model that can support itself but collapse with those being bypassed.

A data file with a 10 ton difference between levels is like this:

1,0,3895.0,0.0,12.0
1,0,3885.0,0.0,24.0
1,0,3875.0,0.0,36.0
1,0,3865.0,0.0,48.0
1,0,3855.0,0.0,60.0
1,0,3845.0,0.0,72.0
.
.
.
1,1,2865.0,0.0,1248.0
1,1,2855.0,0.0,1260.0
1,1,2845.0,0.0,1272.0
1,1,2835.0,0.0,1284.0
1,1,2825.0,0.0,1296.0
1,1,2815.0,0.0,1308.0

The first two fields are flags controlling the program, The third field is the weight in tons. The next field is velocity and the last is height. The file is upside down in that the lightest and highest for the simulated structure is at the bottom of the file.

The data file with an 11% difference between levels is like this:

1,0,36230.4028832,0.0,12.0
1,0,32640.0042368,0.0,24.0
1,0,29405.4093248,0.0,36.0
1,0,26491.3567808,0.0,48.0
1,0,23866.0880608,0.0,60.0
1,0,21500.9778272,0.0,72.0
1,0,19370.2496288,0.0,84.0
.
.
.
1,1,1.063356,0.0,1236.0
1,1,0.9610016,0.0,1248.0
1,1,0.86433,0.0,1260.0
1,1,0.779036,0.0,1272.0
1,1,0.6994,0.0,1284.0
1,1,0.63119,0.0,1296.0
1,1,0.5686,0.0,1308.0

The masses are all independent until they impact when they combine into a single mass with a new velocity based on the conservation of momentum.

This is the result for 10 ton steps:

Tower Array is Loaded with 109 Levels.

=================================================

Collision 1 at 1139.99817216 feet!!!
Mass @: 1140.02411448 ft. hit Mass @: 1140.0 ft. at: 0.864 sec.
2945.0 tons traveling: 27.75408 ft/sec hit 2955.0 tons moving at: 0.0 ft/sec

New mass is: 5900.0 tons moving: 13.8535195932 ft/sec

=================================================

Collision 2 at 1127.99202059 feet!!!
Mass @: 1128.01508422 ft. hit Mass @: 1128.0 ft. at: 1.399 sec.
5900.0 tons traveling: 31.0269595932 ft/sec hit 2965.0 tons moving at: 0.0 ft/sec

New mass is: 8865.0 tons moving: 20.6496403384 ft/sec

=================================================

Collision 3 at 1123.56033432 feet!!!
Mass @: 1123.603422 ft. hit Mass @: 1123.56823633 ft. at: 1.586 sec.
2935.0 tons traveling: 50.9736 ft/sec hit 8865.0 tons moving at: 26.6635603384 ft/sec

New mass is: 11800.0 tons moving: 32.710167661 ft/sec

=================================================

Collision 4 at 1115.99103556 feet!!!
Mass @: 1116.0215188 ft. hit Mass @: 1116.0 ft. at: 1.796 sec.
11800.0 tons traveling: 39.431607661 ft/sec hit 2975.0 tons moving at: 0.0 ft/sec

New mass is: 14775.0 tons moving: 31.4919100102 ft/sec

- - - - - - - - - - - - - - - - - - - - - - - -

Collision 107 at 23.9560787309 feet!!!
Mass @: 24.072225256 ft. hit Mass @: 24.0 ft. at: 11.972 sec.
357915.0 tons traveling: 160.051714258 ft/sec hit 3885.0 tons moving at: 0.0 ft/sec

New mass is: 361800.0 tons moving: 158.333082667 ft/sec

=================================================

Collision 108 at 11.9953237654 feet!!!
Mass @: 12.1513765335 ft. hit Mass @: 12.0 ft. at: 12.047 sec.
361800.0 tons traveling: 160.712922667 ft/sec hit 3895.0 tons moving at: 0.0 ft/sec

New mass is: 365695.0 tons moving: 159.001176994 ft/sec

=================================================

Collision 109 at 0.170591293936 feet!!!
Mass @: 0.302547524866 ft. hit Mass @: 0.2 ft. at: 12.121 sec.
365695.0 tons traveling: 161.348856994 ft/sec hit 0.1 tons moving at: 0.0 ft/sec

New mass is: 365695.1 tons moving: 161.348812873 ft/sec

Mass: # 109 hit the ground at 12.123 sec
365695.1 tons at: 161.380972873 ft/sec

============== This is the result for 11% difference at each level: =================

Tower Array is Loaded with 109 Levels.

=================================================

Collision 1 at 1139.99817216 feet!!!
Mass @: 1140.02411448 ft. hit Mass @: 1140.0 ft. at: 0.864 sec.
2.206323 tons traveling: 27.75408 ft/sec hit 2.450838 tons moving at: 0.0 ft/sec

New mass is: 4.657161 tons moving: 13.1484535424 ft/sec

=================================================

Collision 2 at 1127.99734368 feet!!!
Mass @: 1128.02541125 ft. hit Mass @: 1128.0 ft. at: 1.411 sec.
4.657161 tons traveling: 30.7078135424 ft/sec hit 2.718099 tons moving at: 0.0 ft/sec

New mass is: 7.37526 tons moving: 19.3906698374 ft/sec

=================================================

Collision 3 at 1124.62314462 feet!!!
Mass @: 1124.66677632 ft. hit Mass @: 1124.62982724 ft. at: 1.565 sec.
1.99024 tons traveling: 50.29824 ft/sec hit 7.37526 tons moving at: 24.3433098374 ft/sec

New mass is: 9.3655 tons moving: 29.8589299545 ft/sec

=================================================

Collision 4 at 1115.98175774 feet!!!
Mass @: 1116.00155913 ft. hit Mass @: 1116.0 ft. at: 1.82 sec.
9.3655 tons traveling: 38.0275699545 ft/sec hit 3.019478 tons moving at: 0.0 ft/sec

New mass is: 12.384978 tons moving: 28.756385874 ft/sec

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Collision 107 at 23.9794770425 feet!!!
Mass @: 24.0228671687 ft. hit Mass @: 24.0 ft. at: 20.218 sec.
296729.174731 tons traveling: 63.8970037363 ft/sec hit 32640.0042368 tons moving at: 0.0 ft/sec

New mass is: 329369.178968 tons moving: 57.5649040565 ft/sec

=================================================

Collision 108 at 11.9756128596 feet!!!
Mass @: 12.0151422233 ft. hit Mass @: 12.0 ft. at: 20.416 sec.
329369.178968 tons traveling: 63.9004240565 ft/sec hit 36230.4028832 tons moving at: 0.0 ft/sec

New mass is: 365599.581851 tons moving: 57.5679821641 ft/sec

=================================================

Collision 109 at 0.169207168816 feet!!!
Mass @: 0.202237439797 ft. hit Mass @: 0.2 ft. at: 20.611 sec.
365599.581851 tons traveling: 63.8070221641 ft/sec hit 0.1 tons moving at: 0.0 ft/sec

New mass is: 365599.681851 tons moving: 63.8070047114 ft/sec

Mass: # 109 hit the ground at 20.614 sec
365599.681851 tons at: 63.8713247114 ft/sec

So mass distribution alone changed the time from 12 seconds to 20 seconds.

psik

[Thommo]

And neither is remotely realistic in any way. In the actual collapses the top 25-33 and 11-17 floors rather than the top 1 are the starting mass, and no building has anything like an exponential growth of mass from half a tonne to thirty-six thousand tonnes per floor from top to bottom.

So you've got a 40% variation as being way, way wider range than the real one could possibly be.

[newolder]

psik, Why do you think

1,0,3895.0,0.0,12.0

is different by 11% from

1,0,36230.4028832,0.0,12.0

?
The difference is close to a factor of 10 or 1000% if you must.

Also, 7 decimal places for “weight in tons” is indefensible.

[Thommo]

psik, Why do you think

1,0,3895.0,0.0,12.0

is different by 11% from

1,0,36230.4028832,0.0,12.0

?
The difference is close to a factor of 10 or 1000% if you must.

It's an exponential growth formula for the difference between floors - the 2nd floor is 1.11x(the first floor) the 3rd floor is 1.11x1.11x(the first floor) the 4th floor is 1.11x1.11x1.11x(the first floor) and so on.

It's actually not exactly 11% for some reason and is totally silly, but that's (roughly) what's going on.

[newolder]

psik, Why do you think

1,0,3895.0,0.0,12.0

is different by 11% from

1,0,36230.4028832,0.0,12.0

?
The difference is close to a factor of 10 or 1000% if you must.

It's an exponential growth formula for the difference between floors - the 2nd floor is 1.11x(the first floor) the 3rd floor is 1.11x1.11x(the first floor) the 4th floor is 1.11x1.11x1.11x(the first floor) and so on.

It's actually not exactly 11% for some reason and is totally silly, but that's (roughly) what's going on.

It's a geometric increase between floors then, ok.

[psikeyhackr]

psik, Why do you think

1,0,3895.0,0.0,12.0

is different by 11% from

1,0,36230.4028832,0.0,12.0

?
The difference is close to a factor of 10 or 1000% if you must.

Also, 7 decimal places for “weight in tons” is indefensible.

1,0,36230.4028832,0.0,12.0
1,0,32640.0042368,0.0,24.0

36230.4028832 32640.0042368

The 11% difference is between records in the same data file not between the two data files. The program processes the data files separately.

The number of decimal places in the weight of the floors is nearly irrelevant. The issue is the accumulated collapse time resulting from the effect of the Conservation of Momentum on the resulting impacts of the 100+ masses. Get bent out of shape about the decimal places if you want.

psik

[Thommo]

It's a geometric increase between floors then, ok.

Exactly, and that's why it looks so ridiculous.

ETA: To be fair if you had a geometric/exponential growth of perhaps 0.5% to 1% per floor it wouldn't be ridiculous, it's the size of the exponent that's the problem here.

[newolder]

...

The number of decimal places in the weight of the floors is nearly irrelevant.

Then don't quote them.

The issue is the accumulated collapse time resulting from the effect of the Conservation of Momentum on the resulting impacts of the 100+ masses. Get bent out of shape about the decimal places if you want.

psik

I'll get bent about what I like, thanks.

Also, weight is not measured in tons, that would be mass.

[Xaihe]

It's a geometric increase between floors then, ok.

Exactly, and that's why it looks so ridiculous.

ETA: To be fair if you had a geometric/exponential growth of perhaps 0.5% to 1% per floor it wouldn't be ridiculous, it's the size of the exponent that's the problem here.

I introduced the 11% exponential growth to show with an extreme example that the location of the center of mass and the mass distribution are not relevant to the discussion.

[psikeyhackr]

...

The number of decimal places in the weight of the floors is nearly irrelevant.

Then don't quote them.

The issue is the accumulated collapse time resulting from the effect of the Conservation of Momentum on the resulting impacts of the 100+ masses. Get bent out of shape about the decimal places if you want.

psik

I'll get bent about what I like, thanks.

Also, weight is not measured in tons, that would be mass.

Some people can't use a dictionary.

ton
[tuhn]
noun

a unit of weight, equivalent to 2000 pounds (0.907 metric ton) avoirdupois (short ton) in the U.S. and 2240 pounds (1.016 metric tons) avoirdupois (long ton) in Great Britain.

Also called freight ton.a unit of volume for freight that weighs one ton, varying with the type of freight measured, as 40 cubic feet of oak timber or 20 bushels of wheat.

Maybe you can read but have a comprehension problem.

Weight is mass times gravity but since Earth's 1g is used as a reference 1 ton of mass has 1 ton of weight.

[aban57]

...

The number of decimal places in the weight of the floors is nearly irrelevant.

Then don't quote them.

The issue is the accumulated collapse time resulting from the effect of the Conservation of Momentum on the resulting impacts of the 100+ masses. Get bent out of shape about the decimal places if you want.

psik

I'll get bent about what I like, thanks.

Also, weight is not measured in tons, that would be mass.

Some people can't use a dictionary.

ton
[tuhn]
noun

a unit of weight, equivalent to 2000 pounds (0.907 metric ton) avoirdupois (short ton) in the U.S. and 2240 pounds (1.016 metric tons) avoirdupois (long ton) in Great Britain.

Also called freight ton.a unit of volume for freight that weighs one ton, varying with the type of freight measured, as 40 cubic feet of oak timber or 20 bushels of wheat.

Maybe you can read but have a comprehension problem.

Weight is mass times gravity but since Earth's 1g is used as a reference 1 ton of mass has 1 ton of weight.

Somebody needs to go back to school. I didn't go very far, but I clearly remember P=m*g, P being the wheight, M the mass and g the gravitational acceleration, which is usually rounded to 10, as it's equal to 9.8 something, and different according to where you are on the planet.
Also, mass is measured in kg (or tons for bigger magnitudes) and weight in Newtons. But since in modern common language, weight and mass are interchangeable, you'll find dictionnaries making the same mistake.