900 replies to this topic

[Q24]

flyingswan, on 01 October 2012 - 04:37 PM, said:

If that's your understanding of probability, you should avoid gambling.

No, that is strict definition of the mathematical terms “likely” and “unlikely”.  Gambling is somewhat different, where the bookies’ odds are not necessarily reflective of true probability.  I’d say that everyone should avoid gambling as odds are fixed in the bookies’ favour.  Unless of course it’s just a bit of fun and you’re feeling lucky.

booNyzarC, on 01 October 2012 - 04:46 PM, said:

The problem with your analogy here is that the upper block is never removed.  Drop a large brick on the can and you'd have a closer representation.

The upper block in the analogy, relevant to what LG and I were discussing, is the foot stamping on the can.

booNyzarC, on 01 October 2012 - 04:46 PM, said:

Tell me something Q24, speaking in terms of Bazant's model only, do you think that the core columns continue to provide full (or nearly full) resistance to the upper block until they are completely deformed to the point of full compression?

No, of course those columns that are deformed do not continue to provide full resistance.  Fortunately the upper and lower blocks consist of the same columns and so approximately equal and opposite damage still occurs between them at the crush front.

booNyzarC, on 01 October 2012 - 04:46 PM, said:

What a fascinating representation of your expectations here.  A full and proper response to this will have to wait, but at the outset I'm quite surprised that anyone could possibly think this is what would happen.

Oh god... a full and proper response... but we’ve been over it before booNy.

[Q runs away, arms in air, screaming maniacally]

booNyzarC, on 01 October 2012 - 05:42 PM, said:

When it strikes the next tier, let's say for the sake of the model that the structural elements are insufficient to arrest the momentum which the upper block gathered during its initial descent.  What do you predict would happen if those structural elements buckled, failed, and deformed because of the energy imparted by the impact?  Would it not continue to accelerate due to the force of gravity just as the original upper block accelerated through the first failed tier?

It was better than a knife and butter, but you are still applying all the energy to the lower structural elements only  

[booNyzarC]

Q24, on 01 October 2012 - 05:51 PM, said:

The upper block in the analogy, relevant to what LG and I were discussing, is the foot stamping on the can.

I understand that, but you suggest that the foot be stopped moving down halfway through the can, which is essentially removing the upper block.  This doesn't happen in the collapse.  The actual upper block is never removed.

Q24, on 01 October 2012 - 05:51 PM, said:

No, of course those columns that are deformed do not continue to provide full resistance.  Fortunately the upper and lower blocks consist of the same columns and so approximately equal and opposite damage still occurs between them at the crush front.

The equal and opposite damage is irrelevant to the point.  The point is that the mass of the upper block continues to accelerate due to gravity once those failures occur.

Q24, on 01 October 2012 - 05:51 PM, said:

Oh god... a full and proper response... but we’ve been over it before booNy.

[Q runs away, arms in air, screaming maniacally]

Sorry Q, but I'm only attempting to explain things because we have lack of agreement.  There is only one right answer to the question of whether or not a gravity driven global collapse is possible.  The fact that we disagree on this point means that one of us is right and the other one is wrong.  The only way to reach agreement is to get to the heart of the matter and understand the principles involved.  I, for one, would like to reach agreement with you at some point which is why I continue to engage you in the discussion.

Q24, on 01 October 2012 - 05:51 PM, said:

It was better than a knife and butter, but you are still applying all the energy to the lower structural elements only  

I'm not applying energy to the lower structure only.  I was asking specifically about the lower structure because of the above mentioned point.  Once failure occurs, does gravity continue to accelerate the mass above or not?  This is a key question and one which you seem to keep avoiding for some reason.

You keep claiming that the downward velocity is supplied solely by the momentum of the upper block.  This is a flawed way to look at the problem.  Read my collapse initiation scenario again, where we start with zero velocity and zero momentum.  At the end of descent through the first tier, we have both velocity and momentum but it wasn't imparted by anything other than gravity and it was imparted despite there being 30 structural elements in the way.  This is the most important thing to take on board for understanding the physics involved.

Once you've understood the principle of this, then move on.

After the initial impact the momentum of the upper block contributes to a new downward velocity, but once the structural elements fail both below and above the impact point, the whole portion in motion now continues to accelerate through the failed section due to gravity.

[Babe Ruth]

RaptorBites, on 01 October 2012 - 05:31 PM, said:

The Ross and Furlong paper only talks about the seismic activity before the reported crash times of the flights.  Which is Ross and Furlongs contention along with Willie Rodriguez's testimony that is YOUR submitted proof of controlled demolitions.

At what point of the paper did they talk about blisted paint and melted tires?

This is the reason why it is not even possible to have any form of rational conversation with you BR.

They DID NOT talk about blistered paint and melted tires Swan, and I never said they did.

Tires and paint are but tiny parts of what happened that day that cannot be supported by gravity and jetfuel.  They are tiny parts of a very large pile of circumstantial evidence that you and your mates cannot explain in any sort of persuasive manner.  They are but a few pieces of the evidence that LAYMEN use to describe all the weird events that day that cannot have taken place in a gravity & jetfuel event.

[skyeagle409]

Babe Ruth, on 01 October 2012 - 08:33 PM, said:

They DID NOT talk about blistered paint and melted tires Swan, and I never said they did.Tires and paint are but tiny parts of what happened that day that cannot be supported by gravity and jetfuel.

The jet fuel got things started.

I guess you forgot that you were the person who claimed that molten steel was seen flowing from the WTC building and now, you are claiming the fires were not sufficient enough to weaken steel. If you are going to continue with your deception routine, at least make up your mind.

Edited by skyeagle409, 01 October 2012 - 09:12 PM.

[RaptorBites]

Babe Ruth, on 01 October 2012 - 08:33 PM, said:

They DID NOT talk about blistered paint and melted tires Swan, and I never said they did.

So why when discussion the Ross and Furlong paper, do you detach yourself and bring up another completely different point?

Babe Ruth, on 01 October 2012 - 08:33 PM, said:

Tires and paint are but tiny parts of what happened that day that cannot be supported by gravity and jetfuel.

Here's a simple visual image how gravity and jetfuel can melt and blister paint.  (mind you I am not saying this happened, but actually shows you how funny this argument is to me.)

1. jetfuel leaks out of broken plane
2. jetful leaks out of the building
3. gravity pulls the jetfuel towards the street onto cars
4. buring falling debris falls on car and ignites jetfuel
5. blistered paint and melted tires

So tell me again how gravity and jetfuel can never do that?

Babe Ruth, on 01 October 2012 - 08:33 PM, said:

They are tiny parts of a very large pile of circumstantial evidence that you and your mates cannot explain in any sort of persuasive manner.

For the most part, we have been doing well so far.  Every bit of evidence you have presented so far (regardless of how silly or little it is) has not been held up to scruitny.

Have anything else for us to consider?

Babe Ruth, on 01 October 2012 - 08:33 PM, said:

They are but a few pieces of the evidence that LAYMEN use to describe all the weird events that day that cannot have taken place in a gravity & jetfuel event.

And yet,

Laymen believed a C-130 could fire a cruise missle at the Pentagon <---*snicker*
Laymen believed the passengers of flight 93 were unloaded onto a bus and carted off to a secret location
Laymen believed nukes were used to demolish the twin towers
Laymen believed this was plotted by the NWO
Laymen believed that a cruise missle fired from under the helipad at the Pentagon caused the damage
Laymen believed that pods were attached to the airplanes
Laymen believed that the planes were military planes just repainted to UA and AAL colors

I can go on and on here how the layman got it wrong, multiple times.

[Liquid Gardens]

Q24, on 01 October 2012 - 05:51 PM, said:

The upper block in the analogy, relevant to what LG and I were discussing, is the foot stamping on the can.

Quick point while I have a second, and yes, anyone please feel free to correct me on this.  Q's analogy, which of course as with too many of his analogies does not factor in a gravity component but that isn't relevant for what I'm trying to point out, is somewhat representative of what I was referring to with what happens to the middle layer if we immediately vaporize the upper block.  Q, you asked if I thought if you were crushing a can with your foot and took away would there be more 'damage'; I hate that word, it's not scientific nor does it have a standard scientific measurement that corresponds to it that I'm aware of.  Let's single out the lid of this can and it's mass.  When the foot is moved away, I believe that the lid for an instant is exerting more force on the lower part of the can after the foot is removed than it does when it's whole; the can has to decelerate the motion of the lid, which it does almost instantaneously.  It's not a good analogy because everyone knows how cans behave and that, in human terms, the can will not continue to crumple once the foot is removed; that doesn't mean that it doesn't have to decelerate the lid even if it's undetectable to the eye.  If you don't believe me, change the bottom of the can to a loose spring; I think in that case it's easier to envision that the motion of the lid does continue even if it's just for an instant before the can stops its momentum.  The point being, the mass of the lid (middle section of the tower) does exert more force simply because it has momentum where when the can was whole it does not.  I understand Q's point I think (although I don't agree with how he's treating gravity), you are talking about the net forces; with no other forces acting on it, any momentum the middle layer gains comes from a corresponding loss in the upper block, but just talking about the middle layer, its mass alone is exerting a stronger force on the lower block than before the collapse occurred.  Corrections as always welcomed.

Just wanted to provide some clarification, although again I may be wrong, but this is what Newton's first law means to me.  I think the key question is what boony said, "After the initial impact the momentum of the upper block contributes to a new downward velocity, but once the structural elements fail both below and above the impact point, the whole portion in motion now continues to accelerate through the failed section due to gravity."  I think you would say 'no', Q, although I still don't understand why; I believe you were just referring not too long ago to the fact that the lower block temporarily has even less stress on it for a certain time period after the stories lose their strength and the upper block is falling until it reaches the point of more lower block structure to resist it.

Edited by Liquid Gardens, 01 October 2012 - 10:23 PM.

[booNyzarC]

Liquid Gardens, on 01 October 2012 - 10:15 PM, said:

Quick point while I have a second, and yes, anyone please feel free to correct me on this.  Q's analogy, which of course as with too many of his analogies does not factor in a gravity component but that isn't relevant for what I'm trying to point out, is somewhat representative of what I was referring to with what happens to the middle layer if we immediately vaporize the upper block.  Q, you asked if I thought if you were crushing a can with your foot and took away would there be more 'damage'; I hate that word, it's not scientific nor does it have a standard scientific measurement that corresponds to it that I'm aware of.  Let's single out the lid of this can and it's mass.  When the foot is moved away, I believe that the lid for an instant is exerting more force on the lower part of the can after the foot is removed than it does when it's whole; the can has to decelerate the motion of the lid, which it does almost instantaneously.  It's not a good analogy because everyone knows how cans behave and that, in human terms, the can will not continue to crumple once the foot is removed; that doesn't mean that it doesn't have to decelerate the lid even if it's undetectable to the eye.  If you don't believe me, change the bottom of the can to a loose spring; I think in that case it's easier to envision that the motion of the lid does continue even if it's just for an instant before the can stops its momentum.  The point being, the mass of the lid (middle section of the tower) does exert more force simply because it has momentum where when the can was whole it does not.  I understand Q's point I think (although I don't agree with how he's treating gravity), you are talking about the net forces; with no other forces acting on it, any momentum the middle layer gains comes from a corresponding loss in the upper block, but just talking about the middle layer, its mass alone is exerting a stronger force on the lower block than before the collapse occurred.  Corrections as always welcomed.

Just wanted to provide some clarification, although again I may be wrong, but this is what Newton's first law means to me.  I think the key question is what boony said, "After the initial impact the momentum of the upper block contributes to a new downward velocity, but once the structural elements fail both below and above the impact point, the whole portion in motion now continues to accelerate through the failed section due to gravity."  I think you would say 'no', Q, although I still don't understand why; I believe you were just referring not too long ago to the fact that the lower block temporarily has even less stress on it for a certain time period after the stories lose their strength and the upper block is falling until it reaches the point of more lower block structure to resist it.

Ah, I see the reasoning for the analogy now.  In that sense I think I'd have to say it probably doesn't have momentum because the object (in this case a single can braced against the ground) isn't fully in motion, it is merely deforming from the compressive pressure applied by the foot.  If the can cracked and literally fractured, the portion above the point of fractured would then be it's own isolated object and would attain momentum.

Likewise, if you take two cans, one stacked on the other and compressed fully through the first can without any fracture and partially into the second can before removing the pressure, the first crushed can would have momentum because it is fully in motion.

Perhaps another illustration which might help is a squat rack with safety bars, and the person doing the squats is 'sitting' on a spring which is strong enough to support the lifter's weight but not the weight stacked on the bar.




If the lifter fails under the load, he'll be pushed downward by the weighted bar until the weighted bar is caught by the safety bars.  At that point he will still have momentum moving downward and further compress the spring for a time after the downward motion of the weighted bar is halted, but the spring should quickly catch him and even push him back up into the weighted bar.

Is that kind of what you are describing?


Of course, Q may try to contend that this is precisely what happens with a continuous core and whatnot, but it isn't.  Once one story is fully compressed and the next story is buckling, the initially failed and fully compressed story is fully in motion with the original upper block and lending it's mass (and therefore momentum) to that of the original block.

This is strictly regarding my understanding of Bazant's limiting case by the way.  In reality the collapses were far more violent and chaotic, with the majority of failures being at the weakest points; the joints and other connections, which literally created huge volumes of individually falling chunks all at the same time and striking the structure below in quick succession.


Hope that clarifies, and if I've made any errors in the description hopefully Swanny or someone else will point them out and bring them to light.

[Liquid Gardens]

booNyzarC, on 01 October 2012 - 11:52 PM, said:

Ah, I see the reasoning for the analogy now.  In that sense I think I'd have to say it probably doesn't have momentum because the object (in this case a single can braced against the ground) isn't fully in motion, it is merely deforming from the compressive pressure applied by the foot.  If the can cracked and literally fractured, the portion above the point of fractured would then be it's own isolated object and would attain momentum.

Likewise, if you take two cans, one stacked on the other and compressed fully through the first can without any fracture and partially into the second can before removing the pressure, the first crushed can would have momentum because it is fully in motion.

Perhaps another illustration which might help is a squat rack with safety bars, and the person doing the squats is 'sitting' on a spring which is strong enough to support the lifter's weight but not the weight stacked on the bar.




If the lifter fails under the load, he'll be pushed downward by the weighted bar until the weighted bar is caught by the safety bars.  At that point he will still have momentum moving downward and further compress the spring for a time after the downward motion of the weighted bar is halted, but the spring should quickly catch him and even push him back up into the weighted bar.

Is that kind of what you are describing?

Yes, that's exactly it; for some amount of time, the squatter was still in motion even though the upper weighted bar's weight was removed, something must decelerate him to stop that motion, otherwise he would stay in motion; maybe a spring isn't the best example, maybe a hydraulic support that just resists.  I guess at this point, purely from an intuition standpoint and from way out of my depth here, I'm not understanding why the lid would not have momentum just because it's crumpling or deforming; I don't know why 'deforming' should be separated from 'falling' as far as momentum is concerned.  It seems a little odd to me to say that since the can is an 'object' it behaves differently; we should be able to break up this can into millimeter square pieces of mass and see what each is doing and if it's in motion, I don't know why the same physics wouldn't apply at that level.  These blocks of can are yes feeling a lot of force from being attached to the can but 'objects' moving experience air resistance, it's all just forces isn't it?  The lid has mass, and it's moving, doesn't that necessarily mean momentum period?

I think I may be wrong with my ultimate point though that I'm trying to get to, I'm realizing that I'm not clear on momentum at this point.  I'm having trouble understanding where Q is coming from with the 'holding up the same weight they always have' when things are moving downward, when it seems there must be an 'additional force' from the momentum that is above just the standard gravitational force at rest (?) but I don't think that's the correct way to put it and may not be correct at all even if I could explain it.  More study is needed on my part.

Quote

Of course, Q may try to contend that this is precisely what happens with a continuous core and whatnot, but it isn't.  Once one story is fully compressed and the next story is buckling, the initially failed and fully compressed story is fully in motion with the original upper block and lending it's mass (and therefore momentum) to that of the original block.

I agree, I don't understand how a fully compressed story can behave any other way and can't see how Q can treat a fully compressed story, once subsequent stories beneath it have also compressed, as if it doesn't behave like an extension of the upper block.  I have to think more about his impalement scenario to see if it makes any difference though.

Quote

This is strictly regarding my understanding of Bazant's limiting case by the way.  In reality the collapses were far more violent and chaotic, with the majority of failures being at the weakest points; the joints and other connections, which literally created huge volumes of individually falling chunks all at the same time and striking the structure below in quick succession.

Hope that clarifies, and if I've made any errors in the description hopefully Swanny or someone else will point them out and bring them to light.

It does, I think your squat rack example is an excellent one and a better way of explaining what I'm talking about and comparing to a crumpling can.

[booNyzarC]

Liquid Gardens, on 02 October 2012 - 02:35 AM, said:

Yes, that's exactly it; for some amount of time, the squatter was still in motion even though the upper weighted bar's weight was removed, something must decelerate him to stop that motion, otherwise he would stay in motion; maybe a spring isn't the best example, maybe a hydraulic support that just resists.  I guess at this point, purely from an intuition standpoint and from way out of my depth here, I'm not understanding why the lid would not have momentum just because it's crumpling or deforming; I don't know why 'deforming' should be separated from 'falling' as far as momentum is concerned.  It seems a little odd to me to say that since the can is an 'object' it behaves differently; we should be able to break up this can into millimeter square pieces of mass and see what each is doing and if it's in motion, I don't know why the same physics wouldn't apply at that level.  These blocks of can are yes feeling a lot of force from being attached to the can but 'objects' moving experience air resistance, it's all just forces isn't it?  The lid has mass, and it's moving, doesn't that necessarily mean momentum period?

I think I may be wrong with my ultimate point though that I'm trying to get to, I'm realizing that I'm not clear on momentum at this point.  I'm having trouble understanding where Q is coming from with the 'holding up the same weight they always have' when things are moving downward, when it seems there must be an 'additional force' from the momentum that is above just the standard gravitational force at rest (?) but I don't think that's the correct way to put it and may not be correct at all even if I could explain it.  More study is needed on my part.

This part isn't easy to wrap your head around, I know.  One thing that might help is to consider the properties of the materials in question.  Metals are classified by many different properties; brittleness, malleability, hardness, ductility, elasticity, density, toughness, fusibility, conductivity, etc...  If we just look at a couple of these properties in comparison with other materials it might help to make sense of the concepts.  Consider brittleness and plasticity for a moment when applied to a section of very dry straw as opposed to a length of copper wire.

In both examples imagine that you are holding a 20 inch section of the material with your left hand in a perfectly vertical direction.  Then apply downward pressure with your right hand from the top.

When you exert enough vertical compression on the straw, it fractures quite easily and if you stop exerting pressure after this occurs, the portion above the point of fracture falls.  When you exert pressure on the copper wire, it simply deforms (or bends) and if you stop exerting pressure it doesn't fall because there has been no fracture.  This is a measurement of the material's brittleness.

Now take two more samples from our hypothetical workshop and push down on the straw but not enough to cause it to fracture.  Raise your hand and notice that it returns to its original shape.  Do the same with the piece of copper wire and notice that it retains its deformed shape.  This is a measurement of the material's plasticity.

These different materials have different properties because of their chemical composition and the bonds which hold them together are inherently different as a result.  The same is true of different metals.  So in the case of our aluminum can(s), it (or they) will respond differently from the length of straw, the copper wire, and structural steel alloys.  It is a lot to take in, I agree.

With the case of steel, it is actually a fairly brittle material as far as metals go, especially at lower temperatures.  But it is also very strong and capable of supporting significant static loads as we find in building construction.  This is one of the reasons that blacksmiths use forges to heat steel, not only to soften it but also to prevent fracture while it is being deformed into the desired shape of a blade or whatever else.  This strength is also one of the reasons that it is such a popular material for tall structures like the Twin Towers.

Edit to add:
I didn't really address momentum with the above descriptions, which appears to be one of the key questions needing clarification.  Momentum is a measurement of an object of defined mass in motion.  In our examples above, the objects aren't in motion until fracture occurs.  Instead they are deforming.  Once fracture occurs, the portion above the point of fracture is in motion and it is only when an object has motion that it can have momentum.

Consider a blob of clay.  If you squish it in your palm, it doesn't have motion, it is merely deforming.  If you form into the shape of a ball, set it on the ground, and then strike it with a golf club, it almost simultaneously deforms from the impact of the club and then enters into motion due to the club's momentum.  At that point the deformed mass of clay has momentum of its own.

There are other ways to describe this, but that was the first thought that came to mind.  Does that help make the distinction between deformation and momentum?

Liquid Gardens, on 02 October 2012 - 02:35 AM, said:

I agree, I don't understand how a fully compressed story can behave any other way and can't see how Q can treat a fully compressed story, once subsequent stories beneath it have also compressed, as if it doesn't behave like an extension of the upper block.  I have to think more about his impalement scenario to see if it makes any difference though.

It is hard to say, though through the discussions on this thread his actual reasoning is starting to come more into focus for me.  Thank you for contributing to that by the way because until you started asking the questions that you've been asking and forcing key clarifications, I've been struggling to fully envision how exactly Q24 reconciles his position.  It's starting to be more clear to me now, though admittedly it's a bit fuzzy yet.  So long as the dialogue continues and more information comes out, I think we can reach a point of understanding on all sides.  Or at least I hope so.

Liquid Gardens, on 02 October 2012 - 02:35 AM, said:

It does, I think your squat rack example is an excellent one and a better way of explaining what I'm talking about and comparing to a crumpling can.

That's good to hear, sometimes I wonder if I'm too brief in my descriptions to fully convey my intended point.

Edited by booNyzarC, 02 October 2012 - 03:44 AM.

[flyingswan]

Q24, on 01 October 2012 - 05:51 PM, said:

No, that is strict definition of the mathematical terms “likely” and “unlikely”.  

But it isn't the meaning of "unlikely" that anyone would normally use.

I'm interested in what you think would be unlikely.  Which if any of these, for example?

Cutting a pack of cards and getting an ace?

Rolling 6 on a dice?

Tossing three coins and getting two heads and a tail?

Red coming up on a roulette wheel?

[flyingswan]

booNyzarC, on 02 October 2012 - 03:14 AM, said:

Consider a blob of clay.  If you squish it in your palm, it doesn't have motion, it is merely deforming.  If you form into the shape of a ball, set it on the ground, and then strike it with a golf club, it almost simultaneously deforms from the impact of the club and then enters into motion due to the club's momentum.  At that point the deformed mass of clay has momentum of its own.

Not really how I would look at it.  Deforming clay is essentially a rather viscous fluid, which means that properties like velocity and momentum have different values at different points in the blob.  There is always a mean velocity for the total object, but you can still have parts in motion even when the mean velocity is zero.

Similarly with a deforming structure.  A buckling column may be stationary at its base and have high velocities in varying directions along its length.

[flyingswan]

Liquid Gardens, on 01 October 2012 - 10:15 PM, said:

I understand Q's point I think (although I don't agree with how he's treating gravity), you are talking about the net forces; with no other forces acting on it, any momentum the middle layer gains comes from a corresponding loss in the upper block, but just talking about the middle layer, its mass alone is exerting a stronger force on the lower block than before the collapse occurred.  Corrections as always welcomed.

Perhaps Q24's problem is that he is so obsessed with what he thinks is a violation of Newton's Third Law that he completely misses the explanation which comes from Newton's Second Law, ie if something is accelerating, there must be a force acting on it.

Every bit of the building has gravity acting on it, but during collapse the different parts experience different accelerations, and this gives rise to forces between them.  When the descending upper block first hits stationary structure, it decelerates, so there is an upward force on the upper block and an equal downward force on the lower block.  These forces cause damage and parts break off each block, so you now also have a falling debris layer between the blocks.

Gravity accelerates everything no longer attached downwards, but every impact with stationary structure again results in equal and opposite forces.  It's now the debris layer which interacts with the lower block, while also interacting on its upper side with the upper block.  At both these interfaces there are equal and opposite forces present, but these two sets of forces must be different unless the debris layer is in free fall with no non-gravitational forces acting on it.  Since the debris layer is clearly meeting resistance from the lower block and being slowed to less than free-fall acceleration, there must be a net force acting upwards on the layer.  In other words, the force acting upwards on the debris layer from the lower block must be greater than the force acting downwards on the debris layer from the upper block.

At each interface Newton's Third Law is satisfied, but the two interfaces see a difference in the size of the forces because of the changing momentum of the growing debris layer between the interfaces can  only be caused by such a force difference.

Edited by flyingswan, 02 October 2012 - 10:34 AM.

[Q24]

flyingswan, on 02 October 2012 - 09:15 AM, said:

But it isn't the meaning of "unlikely" that anyone would normally use.

It’s the only strict definition there is of “likely”/”unlikely”.  We cannot just apply our personal interpretations otherwise we end up talking at cross-purposes.  

> 50% means an outcome is likely
< 50% means an outcome is unlikely

flyingswan, on 02 October 2012 - 09:15 AM, said:

Cutting a pack of cards and getting an ace?

7.7%  - unlikely

flyingswan, on 02 October 2012 - 09:15 AM, said:

Rolling 6 on a dice?

16.7% - unlikely

flyingswan, on 02 October 2012 - 09:15 AM, said:

Tossing three coins and getting two heads and a tail?

After the last time, I’m never talking with you about tossing coins again (and actually, after this post, I'm not talking with you about probabilities anymore, because a child could understand this stuff): -

http://www.unexplain...20#entry3073742

The only difference there is that we were talking about “expected” and “unexpected” rather than “likely” and “unlikely”.  That was over 3 years ago... nothing changes.

flyingswan, on 02 October 2012 - 09:15 AM, said:

Red coming up on a roulette wheel?

Red, 48.6% - unlikely
Black, 48.6% - unlikely
Green, 2.7% - unlikely

The above is based on a single 0 wheel.

This explains why a gambler is unlikely to win over a prolonged period.  What is likely, is that the casino is going to take your money.

Of course we could qualify this example further to say that a red is only ‘mildly unlikely’ but still it falls under the category of unlikely.

flyingswan, on 02 October 2012 - 09:25 AM, said:

Not really how I would look at it.  Deforming clay is essentially a rather viscous fluid, which means that properties like velocity and momentum have different values at different points in the blob.  There is always a mean velocity for the total object, but you can still have parts in motion even when the mean velocity is zero.

Similarly with a deforming structure.  A buckling column may be stationary at its base and have high velocities in varying directions along its length.

Well said.

Who hacked flyingswan’s account and wrote this?  Keep up the good work.

I read the first paragraph and thought, “Yes, like a structure breaking apart.”  Then, to my amazement, you confirmed it without me needing to say: “Similarly with a deforming structure.”  

The comment, “stationary at its base” is important and the reason I keep referring to the failure location.  If every failure occurred only at the lowermost connection of each column, and only in the lower block, so the whole lower mass as one could enter immediate downward movement, then I’d agree with LG and booNy.  But that is a nonsense – right from the onset of collapse, areas of the uppermost connections, and those in the upper block, must fail too; across the board, generally equal and opposite to the lower.  This is why, rather than a ‘flat line’ of forces coinciding at each lower ‘floor’, forces during the chaotic destruction are better represented by a ‘zig-zag line’ between the upper and lower blocks.  The end result is that during the crush down, damage must occur to both blocks, until the upper block deteriorates (no longer being a single rigid mass), which observation shows it did, and at which point there is no ‘official theory’ that explains the global collapse.

Speaking of the above, I just came across another amusing computer physics simulation where the creator apparently encountered this inherent 'problem' of the upper block breaking apart.  His solution:  reinforce the upper block, making it stronger than the lower block, so that it would not break: -



This type of one-sided reinforcement would be better known as... 'cheating'.

Oh dear, the problems the official collapse theory creates.

Perhaps this would be better: -



Oh.

It is precisely for these reasons that the official theory of the collapse progression relies on somewhat flexible ‘back of an envelope’ calculations, rather than any computer simulation bound to the laws of physics.

[booNyzarC]

flyingswan, on 02 October 2012 - 09:25 AM, said:

Not really how I would look at it.  Deforming clay is essentially a rather viscous fluid, which means that properties like velocity and momentum have different values at different points in the blob.  There is always a mean velocity for the total object, but you can still have parts in motion even when the mean velocity is zero.

Similarly with a deforming structure.  A buckling column may be stationary at its base and have high velocities in varying directions along its length.

Excellent point.  I felt like I was missing a piece when I was typing that out last night.  So given this, the lid of the can that LG was describing actually would have velocity and therefore momentum.

[flyingswan]

Q24, on 02 October 2012 - 11:15 AM, said:

It’s the only strict definition there is of “likely”/”unlikely”.  We cannot just apply our personal interpretations otherwise we end up talking at cross-purposes.  

> 50% means an outcome is likely
< 50% means an outcome is unlikely
.
.
.
Red, 48.6% - unlikely
Black, 48.6% - unlikely
Green, 2.7% - unlikely

We've obviously been at cross purposes.  I consider "unlikely" to mean low probability, say no more than 5%, but you don't.  You think the building is unlikely to collapse, but you also think red is unlikely to come up next spin at roulette.  On your definition of unlikely, you are right, on my definition, I am right.

Quote

I read the first paragraph and thought, “Yes, like a structure breaking apart.”  Then, to my amazement, you confirmed it without me needing to say: “Similarly with a deforming structure.”

You may think that the load of rubbish that constitutes the rest of your post is somehow logically connected with this statement, but I don't see any logic there at all, just a complete misunderstanding of the subject.

Your toy simulations need a "back of the envelope" reality check.  Neither seems to show any signs of elements buckling, meaning that either very significant physics is missing in the simulation or the elements are much stronger in relation to the mass or distance fallen of the upper block than was the case for the actual towers.

Edited by flyingswan, 02 October 2012 - 12:45 PM.