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Author Topic: Conservation of Momentum in a Gravitational Collapse  (Read 45666 times)

Offline wolfekeeper

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Conservation of Momentum in a Gravitational Collapse
« Reply #25 on: 18/04/2009 01:59:03 »
The reason it's not stronger is because metal has a maximum stress it can survive.

Stress is force per unit area. The area of girder is greater at the base because there's more weight on it, so it needs to be- the engineers optimised (minimised) the amount of girder so that the stress is the same at the bottom as at the top; and then added a 'safety factor' on top; usually a factor of 2 or so.

You could potentially simulate this by using more toothpicks to support the lower, heavier parts.

But unfortunately this means that when the building begins to pancake the proportion of the weight it's designed to withstand is exceeded all the way down, by the same proportion- basically each floor is trying to catch all the floors above it moving downwards, but there's more and more weight moving downwards as the failure propagates.

It's possible to make a building that doesn't fail like this, but it would make the building several times more expensive to build, because each floor would have to survive several times the force than the WTC girders were designed for.
« Last Edit: 18/04/2009 02:06:20 by wolfekeeper »
 

Offline psikeyhackr

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Conservation of Momentum in a Gravitational Collapse
« Reply #26 on: 18/04/2009 03:51:59 »
PS - There seems to be a BIG jump in the number of views.
You mean this thread or your Youtube video?
Is that good :) or bad :(?

This thread.  It was in the low 200s then the next time I checked it was 330.
 

Offline Chemistry4me

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Conservation of Momentum in a Gravitational Collapse
« Reply #27 on: 18/04/2009 03:56:04 »
Hmmm...shows how popular wolfekeeper is. ;)
 

Offline psikeyhackr

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Conservation of Momentum in a Gravitational Collapse
« Reply #28 on: 18/04/2009 10:30:45 »
But unfortunately this means that when the building begins to pancake the proportion of the weight it's designed to withstand is exceeded all the way down, by the same proportion- basically each floor is trying to catch all the floors above it moving downwards, but there's more and more weight moving downwards as the failure propagates.

The sections of columns were 36 feet long.  So there were 38 sections from the top to the bottom of the towers.  Lighter columns that the top would be bending and joints getting out of alignment long before failure would occur at the bottom.

But in order for that to be happening MASS would have to be accelerated from the top.  As my demonstration shows, stationary mass would slow down the falling mass.  It could not come down in less than 18 seconds.  Something had to be taking out the columns.

psik
 

Offline Chemistry4me

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Conservation of Momentum in a Gravitational Collapse
« Reply #29 on: 18/04/2009 11:20:58 »
Is it official that the collapse took less than 18 seconds?
 

Offline psikeyhackr

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« Reply #30 on: 18/04/2009 19:06:38 »
Is it official that the collapse took less than 18 seconds?

Mostly.

http://www.pbs.org/wgbh/nova/wtc/cons-flash.html

psik
 

paul.fr

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Conservation of Momentum in a Gravitational Collapse
« Reply #31 on: 18/04/2009 19:35:23 »
Is it official that the collapse took less than 18 seconds?

Mostly.

So is that a Yes or a No?
 

Offline psikeyhackr

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Conservation of Momentum in a Gravitational Collapse
« Reply #32 on: 18/04/2009 22:15:07 »
Is it official that the collapse took less than 18 seconds?
Mostly.
So is that a Yes or a No?

It's a MOSTLY!

I provided a link with a spokesman from the NIST who talks about the times.

Of ourse people on JREF said he misspoke when I brought this up.

psik
 

Offline Chemistry4me

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« Reply #33 on: 19/04/2009 02:21:04 »
Okay, if you say so.
 

Offline psikeyhackr

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Offline psikeyhackr

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« Reply #35 on: 21/04/2009 15:48:25 »
Of course the distribution of mass is also related to analyzing the impacts.


The NIST says the south tower moved 12 inches at the 70th floor even though that was 130 feet below the impact point.  How much energy the building absorbed without doing structural damage would be necessary to know in order to figure out how much energy DID do damage.  Distribution of mass would be necessary for that analysis.

psik
 

Offline L_D

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Conservation of Momentum in a Gravitational Collapse
« Reply #36 on: 23/04/2009 09:16:10 »
Is it official that the collapse took less than 18 seconds?

Yes, according to the 9/11 commission report they fell in 10 seconds. 10 seconds is unrealistically fast looking at the video footage and the true collapse times would more likely be 14 to 16 seconds.

WRT Conservation of Momentum and the collapse of the Towers, if you could remove all the columns and just have the floors magically hovering until they were impacted then the mass alone of the hovering floors would still slow the collapsing mass more than what happened on 9/11. I guess a similar point is being made in the opening post of this thread.

That's even without considering any losses from the system, like the very significant energy needed to pulverise all the concrete which must slow the descent, and the huge amounts of mass that is billowing outwards and therefore cannot assist in collapsing the lower portion because it is falling outside of the collapse.

I think the Towers were brought down by explosives as was the third highrise to fall that day, WTC 7. Please have a look at this short video of WTC 7 collapsing if you are not familiar with it:


If you want to have a look at what is happening under the dust clouds when the Towers collapse then this clip has a very good angle, and it also explains how the Towers fell so quick (because they were blown to smitherines)...


psikeyhackr, I hope to have a good look at your video when I get back from a short holiday.

 

Offline Chemistry4me

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Conservation of Momentum in a Gravitational Collapse
« Reply #37 on: 23/04/2009 10:03:35 »
So are you and psikeyhackr on the same page here about this WTC business? Except you seem to have a theory that they were blown up! Or is that just my misunderstanding? :)
 

Offline dentstudent

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« Reply #38 on: 23/04/2009 10:07:40 »
What we have are either trollers or conspiracy theorists, neither of which stand up to scrutiny nor have a place on a scientific thread (IMHO).
 

Offline L_D

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« Reply #39 on: 23/04/2009 10:11:53 »
So are you and psikeyhackr on the same page here about this WTC business? Except you seem to have a theory that they were blown up! Or is that just my misunderstanding? :)


That's correct, there are millions around the world who, based on the evidence, think the same.

Here are also over 600 architects and engineers who are publicly saying the same thing (if you look on the right hand side of the page you will see the main reasons)..

http://www.ae911truth.org/ [nofollow]

 

Offline Chemistry4me

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Conservation of Momentum in a Gravitational Collapse
« Reply #40 on: 23/04/2009 10:14:45 »
So you're saying there were also terrorists at the bottom of the buildings and they detonated the bombs when the plane crashed? Or maybe there were just bombs put into place? ??????
 

Offline L_D

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Conservation of Momentum in a Gravitational Collapse
« Reply #41 on: 23/04/2009 11:02:46 »
So you're saying there were also terrorists at the bottom of the buildings and they detonated the bombs when the plane crashed? Or maybe there were just bombs put into place? ??????


I only have time for a very quick reply, most people who have looked at all the evidence and concluded that explosives HAD to have been used to bring WTCs 1 2 and 7 down as quick and completely as they did, also believe that the buildings were pre-laced for complete demolition, hence the saying "9/11 was an inside job".

Google 9/11truth and you will find thousands of websites on the subject, both for and against.

The planes and supposed terrorists were nothing more than a sideshow to the false flag operation that 9/11 was, and were inconsequential to the collapses that occured that day (most would also believe that the planes were remotely flown into the buildings and the supposed terrorists were just patsies).
 

Offline psikeyhackr

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« Reply #42 on: 23/04/2009 15:02:14 »
So are you and psikeyhackr on the same page here about this WTC business? Except you seem to have a theory that they were blown up! Or is that just my misunderstanding? :)

I am not talking about what caused the buildings to come down.

I am saying that if planes, fire and gravity are all that caused the WTC1 and WTC2 to come down then it should be possible to analyze and explain everything almost second by second from impact through collapse with all of the computing power we have today.

The Empire State Building was completed 70 years before the WTC was destroyed.  What kind of electronic computers did they have back then?  Skyscrapers must hold themselves up and withstand the wind therefore the designers must determine how much steel and concrete to put on every level.  Therefore how can a SCIENTIFIC ANALYSIS be done without that information?

Science is not about BELIEVING. Science is about KNOWING.  People that want to dismiss this as unscientific but haven't been DEMANDING to know the TONS of STEEL and TONS of CONCRETE on every level of the towers for the last SEVEN YEARS are full of crap.  Those so called architects and engineers at AE911TRUTH haven't been talking about that .  I have emailed them twice.

I have been to one of Richard Gage's seminars.  It comes across as propaganda rather than science to me.

psik
 

Offline wolfekeeper

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Conservation of Momentum in a Gravitational Collapse
« Reply #43 on: 23/04/2009 15:48:32 »
WRT Conservation of Momentum and the collapse of the Towers, if you could remove all the columns and just have the floors magically hovering until they were impacted then the mass alone of the hovering floors would still slow the collapsing mass more than what happened on 9/11.
If it couldn't physically fall down even if the columns had been removed by explosive (yeah, right) then how did it get to flat from up?

So you're saying that it was collapsed by an alien force field or invisible rockets? Or was it all a giant hologram? Perhaps it never actually fell down at all?

You're not making any sense at all.
 

Offline Chemistry4me

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« Reply #44 on: 24/04/2009 01:26:21 »
You want a petition signed Mr. psikeyhackr?
 

Offline psikeyhackr

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« Reply #45 on: 24/04/2009 03:14:24 »
You want a petition signed Mr. psikeyhackr?

Do the laws of physics give a damn about a petition?

This ain't politics.  This is PHYSICS!!!

Do you understand why the distribution of steel and concrete in the WTC  is important to analyzing the supposed collapse or not?  Are you interested in SCIENCE or not?

So do we expect high school kids to BELIEVE airliners could bring down the towers or UNDERSTAND why they could not?  9/11 is such a global event it involves global education.

http://911research.wtc7.net/materials/contrib/911_physics_v9a.htm

I have been to a website where I read a post by somebody complaining about science education in New Zealand.

psik
« Last Edit: 24/04/2009 03:21:06 by psikeyhackr »
 

Offline Chemistry4me

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« Reply #46 on: 24/04/2009 03:17:18 »
Alright alright, just calm down matey. Of course I understand.
 

Offline psikeyhackr

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« Reply #47 on: 24/04/2009 23:27:57 »
Alright alright, just calm down matey. Of course I understand.

WHAT?  I'm always calm it's one of those Vulcan things.

Actually I'd like to beat a lot of these so called Truthers over the head.  With them running around screaming INSIDE JOB and talking about JFK and Pearl Harbor.

Science is a TRUTH MOVEMENT.

Grade school kids all over the planet should be laughing at engineers in the United States.


psik
 

Offline psikeyhackr

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Conservation of Momentum in a Gravitational Collapse
« Reply #48 on: 01/05/2009 17:32:45 »
There is something very curious about the nitwits in authority.

If you download the 10,000 page NCSTAR1 report and search it for "conservation of momentum" you will only find two occurrences.

In one case it refers to the analysis of air flow in a fire.  In the other case it is about the effect of the airliner impact on the trusses supporting the floor slabs. 

But about the ALL IMPORTANT effect of conservation of momentum on the overall collapse of the entire building they say nothing.  How  do you explain people claiming to be world renowned experts ignoring the obvious?

Didn't anybody like Cartoon Physics?   ;D

psik
 

Offline psikeyhackr

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Conservation of Momentum in a Gravitational Collapse
« Reply #49 on: 10/05/2009 06:24:12 »
More views but no responses in a week.

Fall of Physics

The people who claim the WTC towers underwent a gravitational collapse seem to exaggerate what gravity can do. This is a table showing the velocity and distance fallen by an object from a stationary start. In the first 1/10th of a second the mass moves less than 2 inches and is only traveling at 3.2 ft/sec. So a gravitational collapse of the WTC meant the falling top portion must have accelerated what it struck much more than gravity could have and also have broken whatever was supporting that intact portion of the building.

Code: [Select]
.           v == initial velocity
    Time    V = at + v     D = 1/2 at^2 + vt
               v = 0
    00.1     3.2 ft/sec    0.16 ft   1.92 in.
    00.2     6.4 ft/sec    0.64 ft   7.68 in.
    00.3     9.6 ft/sec    1.44 ft  17.28 1n.
    00.4    12.8 ft/sec    2.56 ft
    00.5    16.0 ft/sec    4.00 ft
    00.6    19.2 ft/sec    5.76 ft
    00.7    22.4 ft/sec    7.84 ft
    00.8    25.6 ft/sec   10.24 ft
    00.9    28.8 ft/sec   12.96 ft
    01.0    32.0 ft/sec   16.00 ft
    01.1    35.2 ft/sec   19.36 ft
    01.2    38.4 ft/sec   23.04 ft
    01.3    41.6 ft/sec   27.04 ft
    01.4    44.8 ft/sec   31.36 ft
    01.5    48.0 ft/sec   36.00 ft
    01.6    51.2 ft/sec   40.96 ft
    01.7    54.4 ft/sec   46.24 ft
    01.8    57.6 ft/sec   51.84 ft
    01.9    60.8 ft/sec   57.76 ft
    02.0    64.0 ft/sec   64.00 ft

No matter what brought the towers down the conservation of momentum cannot have been violated. This is the equation for an inelastic collision in which two masses stick together. If the second mass is stationary then v2 is zero.

Conservation of Momentum:

(m1 * v1) + (m2 * v2) = (m1 + m2) * v3

This means the ratio of the stationary mass to the impact mass greatly affects the resulting velocity. If the impact mass is smaller then it will be slowed considerably, but in the opposite case the velocity of the stationary mass will change a lot. But in a gravitational collapse there will be the additional effect of gravitational acceleration before and after impact.

So I have done the calculations for 3 "magical" cases. In each case four masses are magically suspended and when struck from above each mass is released with no resistance. In case #1 the 4 masses are are equal, 2.5 tons each. In case #2 the masses are in the sequence 1, 2, 3 and 4 tons from top to bottom. Case #3 is the reverse sequence of 4, 3, 2 and 1 ton. When the masses are struck from above they begin moving on the basis of conservation of momentum and undergo gravitational acceleration until the next object is struck. Case #0 is just a 10 ton mass dropped from 64 feet with no impacts and is used as a reference case.

Code: [Select]

 .            mass 1     mass 2      mass 3        mass 4
             64 feet   feet 48      feet 32      feet 16
                 
    Case 0    10 ton      0            0            0
    speed       0        32          45.25        55.43         64 ft/sec     
    time        0         1           1.41         1.73         2 sec

    Case 1    2.5 ton    2.5          2.5          2.5
    speed       0       32 16     35.78 23.85  39.91 29.93      43.82 ft/sec
    time        0         1       1.618 14%     2.12 23%       2.554 sec 28%

    Case 2    1 ton       2            3            4
    speed       0       32 10.67  33.74 16.87  36.17 21.70      38.66 ft/sec
    time        0         1       1.721 22%    2.324 34%       2.854 sec 43%

    Case 3    4 ton       3            2            1
    speed       0       32 18.29  37.35 29.05  43.23 38.91      50.37 ft/sec
    time        0         1        1.58 12%    2.023 17%       2.381 sec 19%



The Case line specifies the weight of mass at each of the 4 heights, 64, 48, 32 and 16 feet. These heights were chosen because they correspond to the "1/2 * 32 feet/sec^2" that is in the distance from acceleration equation thereby making calculations easier.

The speed line has the velocity of the net mass before and after impact based on conservation of momentum.

The time line has the time for the mass to fall to that point and the percentage difference from Case 0.

A body in freefall dropped from the top of the World Trade Center would have taken 9.2 seconds to reach the ground. The NIST says the tower that took longer to collapse did it in 11 seconds. So that is only 20% longer than the freefall time. But the WTC collapses required that the tens of thousands of tons of steel and concrete which had held up the buildings for 28 years be bent and broken and crushed. So how is it that only my absurd and miraculous collapse with inverted masses and disappearing supports comes down that fast in relation to freefall? A skyscraper must be bottom heavy and Case #2 using that distribution has double that percentage of time but it didn't require kinetic energy be used to break supports.

So what is the story with all of these people that claim there was a gravitational collapse but also pretend that knowing the TONS of STEEL and TONS of CONCRETE on every level isn't necessary? I have demonstrated that changing the distribution of mass alters the collapse time regardless of the strength of the material involved and how much kinetic energy would be required to break it.

Time and velocity calculations after impacts:

Code: [Select]

.   After Impact #1:
    Case 1: 16 = 16t^2 + 16t     1 = t^2 + t          t = 0.618  19.78+16
    Case 2: 16 = 16t^2 + 10.67t  1 = t^2 + 0.666875t  t = 0.721  23.07+10.67
    Case 3: 16 = 16t^2 + 18.29t  1 = t^2 + 1.143125t  t = 0.58   18.56+18.79

    After Impact #2:
    Case 1: 16 = 16t^2 + 23.85t  1 = t^2 + 1.490625t  t = 0.502  16.06+23.85
    Case 2: 16 = 16t^2 + 16.87t  1 = t^2 + 1.054375t  t = 0.603  19.30+16.87
    Case 3: 16 = 16t^2 + 29.05t  1 = t^2 + 1.815625t  t = 0.443  14.18+29.05

    After Impact #3:
    Case 1: 16 = 16t^2 + 29.93t  1 = t^2 + 1.870781t  t = 0.434  13.89+29.93
    Case 2: 16 = 16t^2 + 21.70t  1 = t^2 + 1.35625t   t = 0.53   16.96+21.70
    Case 3: 16 = 16t^2 + 38.91t  1 = t^2 + 2.431875t  t = 0.358  11.46+38.91

http://www.richarddawkins.net/forum/viewtopic.php?p=1058903#p1058903

No one on richarddawkins.net has found any flaws in the math since July of 2008, not even the man claiming to be a structural engineer.  He just complained about left brained physics.  LOL

Actually I think the people have chosen to BELIEVE the Officail Conspiracy Theory have chosen to ignore this.

psik
« Last Edit: 27/11/2009 00:27:18 by psikeyhackr »
 

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Conservation of Momentum in a Gravitational Collapse
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