If it doesn't agree with experiment, it's wrong. Part II

[jaydeehess]

No. Just, no.

From - https://www.khanacademy.org/science.../acceleration-tutorial/a/acceleration-article

[qimg]https://ka-perseus-images.s3.amazonaws.com/1a144eed22c1be721d2f1537fd164d93bb52dd4f.png[/qimg]

What does the above image clearly show? .

That in order to avoid confusion THEY DON'T USE THE AMBIGUOUS TERM "DECELLERATION".

 

[PhantomWolf]

I do understand what is going on

No you don't, you demonstrated that repeatedly.

and I'm about to destroy your model and your gross misunderstanding of physics.

Actually you're about to give everyone a very big belly laugh. I suggest you give up the physics, which you have already admitted numerous times that you're not an expert in, and instead take up comedy. Trust me, you'd be a total hit on the University tours. You'd have them rolling in the aisles.

Here is your model

[qimg]http://www.internationalskeptics.com/forums/picture.php?albumid=1203&pictureid=10663[/qimg]

Well at least you get one thing correct.

F+ and F- are unnecessary.

Incorrect.

Your claim is,

Wrong. Wrong. Wrong.

Usually one gloats after getting things right, not right before making a fool of themselves, but....

What you should have said is that G⁺ = N^-.

Ummm... No I shouldn't have. You see Forces are Vectors and thus have both a magnitude and a direction. G⁺ and N^- may have the same magnitude, but their directions are different, thus they are not equal anymore then 1 is equal to -1. G⁺ and N⁺ are equal in magnitude and force, in this particular example.

Your claim that G⁺ = N^- is simply incorrect.

If you wanted to take it to an unnecessary level, you could add the absolutely negligible magnitudes of the forces of G^- and N⁺. Those forces are so minute, they are irrelevant when discussing macro physics and the collapse of 110 story buildings.

I have to say that this is where I got the biggest laugh. In accordance to Newton's 3rd Law, the magnitude of G^- = the magnitude of G⁺, and the magnitude of N⁺ = the magnitude of N^-. Since we also know that the magnitude of G⁺ = the magnitude of N⁺ for this model, all four forces, G⁺, G^-, N⁺, and N^- all have the exact same magnitude.

Thus if, as you claim, "Those forces are so minute, they are irrelevant when discussing macro physics and the collapse of 110 story buildings." then so are G⁺, and N^-, so you are claiming that the Gravitational forces on the building are so minute that they are irrelevant when discussing macro physics and the collapse. Seriously, you are way out of your depth here.

Your claim is that the earth exerts a gravitational force on the building pulling it downwards. That part is correct. You then claim that the building exerts a gravitational force on the earth, with the exact same magnitude but the opposite direction. That last part is absolutely wrong. It is massive error in understanding what is actually happening.

You really are showing off your total ignorance in this matter, you should stop embarrassing yourself and try and learn what you are being taught by people instead of doubling down and making it worse.

The Gravitational Force that an object with mass M₁ applies to an object with mass M₂ when at a distance of R between each object's CoM is....

F_G = GM₁M₂/R²
As you can see, it doesn't matter if we are looking at the Earth being M₁ and the Building M₂, or the Building being M₁ and the Earth M₂, the result is exactly the same. The building applies the exact same gravitational force on the Earth that the Earth applies on the building. Newton agrees.

Do any of these credible sources have any diagrams that support your model? No, they don't. I know you won't listen to me, but you should listen to them.

https://www.khanacademy.org/science...ontact-force/v/normal-force-and-contact-force

https://www.youtube.com/watch?v=8_iatWOe4V0

https://www.youtube.com/watch?v=nSYJtRfaDfY

http://www.sparknotes.com/physics/dynamics/newtonapplications/section1.rhtml

http://www.physicsclassroom.com/class/newtlaws/Lesson-2/Types-of-Forces

Yet again you prove that it is possible to use Google and spectacularly fail to understand the results you get.

Not one of those credible sources has a model that confirms your model is correct. Not one. What is the only logical conclusion? The only logical conclusion is that the credible sources prove that your model, and your understanding of physics, is wrong.

Okay, let me try and help you understand. These links are only dealing with the forces N⁺, and N^- in the model I gave you. Why? Because they are dealing solely with the Weight/Normal Force pairing, that is the Weight (N⁺) and the Normal Force (N^-). Since none of then are dealing with the Gravitational Attraction the diagrams they use are truncated to not include it. In fact the diagrams you show are actually virtually identical to mine, other then that they are missing Gravitational Attraction because it's outside the scope of their lesson.

This is what I keep telling you, you can Google stuff, but because you fail to understand what it is you are Googling you make incorrect assumptions.

The sad thing is that you were then given an example that did include Gravitation Attraction in its diagram, and even noted that the Normal was not the opposite pair to Gravitational Attraction, and you hand waved it away. It's sad because had you read it you might have learned something, but instead you wallow in your ignorance thinking you are wise.

It's even clear that you failed to watch your only videos. In the second one you posted the narrator discusses pushing the block up against the bottom of the table which then creates a Normal Force that has a direction the same as Gravitational Attraction. How does that work if they are opposing pairs?

Consider this. A Sky Diver jumps out of a plane. Gravity is applying a force to the skydiver. According to Newtons 3rd Law, there must be an opposite and equal force to this. Since the skydiver is in freefall there is no Normal Force, so what is the equal and opposite force demanded by the 3rd Law?

 

[Dave Rogers]

This is what I keep telling you, you can Google stuff, but because you fail to understand what it is you are Googling you make incorrect assumptions.

Otto: "Apes don't read philosophy."
Wanda: "Yes they do, Otto. They just don't understand it."

Dave

PS: Prediction: FalseFlag will respond "Please show me anywhere I haven't understood Newton's Laws."

 

[tsig]

At the instant of impact the brick will experience a change in acceleration. Newton's third law says this will happen, and we know Newton's third law is true based on numerous observations and experiments.

Your claim that the acceleration after impact will never be zero is not correct. There are scenarios where the paper could stop the brick. It depends on what type of paper is used, and the force exerted by the brick on the paper.

You changed your example to rice paper. If the force exerted by the brick is great enough, the paper might not stop the brick. The acceleration will still change at the instant of the impact.

Paper wraps brick, brick dulls scissors, scissors cuts papers therefore the building could never fall.

 

[tsig]

I'm not looking for answers, FF, I am looking for some semblance of understanding. Some glimmer of hope that you aren't beyond help. Some tiny little thing which suggests you have some cognitive powers capable of seeing how wrong you have been to date. Your post 2319 is just full of wrongness, on an epic and embarrassing scale.

given his misunderstandings I'm surprised he isn't worried about his bridge falling on him.

 

[sts60]

...From - https://www.khanacademy.org/science.../acceleration-tutorial/a/acceleration-article

My undergraduate degree was in physics, and it was from a real university, not the University of Google. Quoting basic physics Web pages doesn't impress me and it doesn't help you. I'll explain why.

[qimg]https://ka-perseus-images.s3.amazonaws.com/1a144eed22c1be721d2f1537fd164d93bb52dd4f.png[/qimg]

What does the above image clearly show?

The "speeding up" case (positive acceleration and positive velocity) corresponds to the brick-through-tissue scenario, since everyone's agreed that down = positive.

Here is the exact relevant text from that page, "Another way to say this is that if the acceleration has the same sign as the velocity, the object will be speeding up. And if the acceleration has the opposite sign as the velocity, the object will be slowing down. "...

Yes, I know. I didn't even need my physics degree for that. In our toy scenario of brick-falling-through-tissue, the net acceleration always has the same sign as the velocity. That's what Redwood, myself, and others have been telling you.

[qimg]http://www.physicsclassroom.com/mmedia/kinema/avd.gif[/qimg]

What does that image clearly show? It shows an object slow down when the acceleration changes.

That image shows three cases: a uniform acceleration down a slope, a change of direction around a curve (with additional downward acceleration from the gravitational force), and a deceleration purely due to friction force. But an object does not necessarily slow down when the acceleration changes. It doesn't in the brick-through-tissue case, since the acceleration never becomes negative.

<snip more materials from the University of Google>

Your first quotation is talking about a "negative" net force, which is not the case we are talking about.

Your second quotation just gives more basic discussion. I don't need it; I learned this stuff, literally, in eighth grade.

What you are saying is that the overall velocity of the brick will not change just because of the impact of the brick. This statement is actually correct. Where you are wrong, as the credible sources show you, is at the instant of impact the brick will experience a force in the opposite direction.

Yes, I said that. The brick experiences a small negative force from the tissue, which is much smaller in magnitude than the gravitational force acting on the brick.

This will, only for an instant, change its velocity. Since acceleration is defined as the change in the velocity vector in a time interval, divided by the time interval, acceleration must also change.

Your thinking is muddy here. The small negative force imparted by the tissue reduces the net positive force acting on the brick, which means that the acceleration changes "only for an instant". During that very short "instant", the velocity continues to increase, just not quite as fast as before the brick hits the tissue. That does not mean it slows down.

What is correct is to say that at a given time after the impact, the [ETA: magnitude of the] velocity of the brick will be very slightly less than what it would have been if no tissue had been there.

Where you are confusing the issue is that the brick continues to accelerate after the impact because of the force due to gravity.

No, I understand this perfectly. I told you that. The brick is accelerating before the impact. The brick is accelerating during the impact. The brick is accelerating after the impact.

You seem to think, as far as I can tell, that the brick somehow decelerates (loses forward speed) during the impact. Remember how, last time I asked you how you validated your application of "basic physics" to complex collapse problems, that I assumed for the sake of argument that you had verified your "basic knowledge" first?

It appears you did not do that. If you think that the brick actually decelerates in our toy scenario, you literally do not understand mechanics at the 8th-grade level.

Also, please don't cite more popular science web sites at me, especially when you don't interpret what they're saying correctly. Remember how you said of someone else, "...[his] conclusions are those of an average person, not a person who is a scientist, architect, or engineer. Because of this, I do not give any credibility to [his] conclusions"?

I don't give any credibility to your conclusions regarding this toy scenario, and therefore to your confidence in your "basic knowledge", not because you are a layman, but because - if you think the brick slows down anytime in this scenario - you don't understand what is happening.

If that is the case, you're in even worse shape than I thought, and the issue that you haven't validated your application of your simple knowledge to a complex problem has to take a back seat to the issue that your "basic knowledge" is, basically, broken.

FalseFlag, I'm trying to help you here. But if you stubbornly refuse to even consider that you might be wrong about a simple toy physics problem, how can you possibly hope to progress in your understanding of more complex problems? In other words, how do you hope to learn anything?

 

[tsig]

You're right. I will never modify my position, because I know I am right. I have provided links to credible sources that show I am right.

Where you're wrong is that you assume I will keep playing the games that are going on here. That is not going to happen.

So you are not going to play the game by continuing to hit the submit button?

 

[tsig]

Why do you keep bringing up scale?

Because your posts sound fishy.

 

[HSienzant]

Please show me a correct free-body diagram where this is taken into account, and why it matters. Once you do that, please show why it proves I am wrong.

I can't believe that this is all you have left. You know I'm right. All you can do is to move the goalposts to complicate the discussion as much as possible. That is all you can do. You have nothing else left.

You have also failed to show why an understanding of Newton's Law of Universal Gravitation is even remotely necessary to see what actually happened during the collapse of WTC1, WTC2, WTC7. Here, I will do your work for you. You haven't shown me why I need to understand this because it is absolutely irrelevant.

Stop wasting your time. Your tricks are transparent, ineffective, and the only thing they prove is how much you must grasp at the most trivial concepts to try to discredit me.

Just an observation. The more you post, the more you sound like Donald Trump to me.

 

[turingtest]

So then it clearly has nothing to do with any conspiracies of Truther claims, so why is this thread in this forum?

I'm sort of wondering the same thing- I thought the whole point of Truther claims was to demonstrate that what started the collapse could not have been the collisions/fires, but must have been CD, thermite, whatever. And now FF is saying

You can claim the collapse was started by whatever you want... Cole does not make any attempt to show what started the collapse, and neither have I.

It seems to me FF has it backward- it doesn't matter what happened after initiation (which is, IIRC, why NIST didn't attempt to model anything after), but what brought it on, so Cole's experiments are irrelevant, even aside from the scaling issue.

 

[HSienzant]

No comment necessary.

Dave

Beat me to it!

Hank

 

[WilliamSeger]

I'm sort of wondering the same thing- I thought the whole point of Truther claims was to demonstrate that what started the collapse could not have been the collisions/fires, but must have been CD, thermite, whatever. And now FF is saying


It seems to me FF has it backward- it doesn't matter what happened after initiation (which is, IIRC, why NIST didn't attempt to model anything after), but what brought it on, so Cole's experiments are irrelevant, even aside from the scaling issue.

I think the "reasoning" is that if collapse continuation was impossible without explosives, then that means there must have been a hoax, so the initiation was likely explosives, too.

I haven't had much luck getting FF to state exactly what he thinks Cole's argument is and what he thinks the experiments mean, but his claim that Cole is simply demonstrating laws of motion is absolutely not true. When Cole's model doesn't behave like the WTC, he immediately claims (ETA: or at least deliberately implies) that the reason must be that WTC was a CD -- the very conclusion he set out to reach -- and he is apparently completely oblivious as to why that logic is nonsense.

 

[pgimeno]

The forces are indeed equal. The accelerations they induce are different (a = F/m). The Earth laughs at a 500N force, because with a mass of approx. 5.972 × 10²⁴ kg, the acceleration it exerts is about 0.00000000000000000000008 m/s².

Just to put this number into perspective: the smallest atom, a hydrogen atom, has a radius of about 25,000,000 attometres. A force of 500 N on the Earth would cause it to accelerate by less than a ten-thousandth of an attometre per second per second.

 

[NoahFence]

Originally Posted by FalseFlag View Post
You're right. I will never modify my position, because I know I am right. I have provided links to credible sources that show I am right.

Where you're wrong is that you assume I will keep playing the games that are going on here. That is not going to happen.

What exactly is it that you're "right" about?

 

[Wolrab]

I have an Associates Degree in Science. Since scale doesn't matter, I am calling myself a doctor.

 

[Redwood]

Originally Posted by Redwood
For the umpteenth time, nobody, but nobody has ever denied that the direction of any force depends on scale.

Yes, they have.

Au contraire. From the first, everyone was laughing at Cole's ridiculous straw man argument.

Originally Posted by Redwood
But scale matters in modeling. I'm going to give you the benefit of the doubt and assume that you are simply too obtuse to understand this. But I'll give it one last try.

You are only proving that you refuse to accept what is true. You say that scale does not matter when talking about directions of net force, then, once you realize the implication of your statement, you try to obscure it with your modeling nonsense.

I can't say I didn't give an honest effort to make you understand. Your failure is your own problem

Originally Posted by Redwood
An elephant's legs can support more weight (a static force) than a squirrel's. But while a squirrel can easily leap 15 ft. out of a tree and absorb the impact (a dynamic force) and scamper away, if you drop an elephant dropped the same 15 ft. it breaks its legs and probably dies. The difference is scaling. Capisce?

Your example has nothing to do with Cole's experiments. Nothing. Not even a little.

Let me make one last effort to explain this to you. We'll leave aside the fact that Cole doesn't even attempt to model the Twin Towers. Lets take a perfect 1/300 scale model of the Eiffel Tower. All the parts are proportionatel, and it's made of the same material. At one meter tall, it would make a dandy garden decoration, but any engineer will tell you that it's useless for an engineering comparison to the original. (It's that darned square-cube scaling law.)

The scale model would doubtless make a pretty good improvised battle club, able to withstand enormous accelerations both when swung and when it strikes its target.

But what happens if, in a battle of giant robots, one of them attempted to use the real Eiffel Tower as a battle club? The whole thing would fall apart! It couldn't possibly survive the same accelerations as the miniature scale model. It's that damned scaling again! (Scaling would also make the existence of giant robots itself problematic.)

Originally Posted by Redwood Everything "displays Newton's laws", from the motion of the planets about the sun (except for that pesky Planet Mercury ) to a video of my living room with everything lying motionless. A small child plopping herself down in a chair displays Newton's laws. A fat man plopping himself down in a chair, breaking it, displays Newton's laws. But Newton's laws don't explain WHY the chair broke under the fat man but not for the little girl. Other laws of physics must be resorted to.

You have to be kidding. Yes, Newton's laws do explain why a chair might break when a larger man sits on it.

Newton's second law says F=ma. The larger man exerts a larger force on the chair, because the larger man has a larger mass. If a chair breaks, it can't support the force being exerted by the object it is trying to support.

No, I'm not kidding. This is a matter of deep understanding. You fail at even a superficial understanding, but I'll give it a try.

Indeed, Newton's Laws of Motion describe what is happening, and even tell you that the fat man exerts a larger force than the little girl. (The Laws of Motion come in because, as I said, they "plop" themselves into it.) But Newton's Laws do not explain why the chair broke under the fat man. One could say that the force exerted by the fat man "exceeded the resistability of the chair", but this is mere tautology. (Richard Feynman would have a good over that.) To explain why, or to explain why a throne survives both the fat man and the little girl, one must resort to other physical laws.

Which brings me to the big point: Newton's Laws of Motion are useless for explaining the why of progressive building collapses. Other physical laws must be used. (I'm sure that Ozeco espectially appreciates this. )

 

[PhantomWolf]

But what happens if, in a battle of giant robots, one of them attempted to use the real Eiffel Tower as a battle club? The whole thing would fall apart! It couldn't possibly survive the same accelerations as the miniature scale model. It's that damned scaling again! (Scaling would also make the existence of giant robots itself problematic.)

Works pretty well in Hollywood, they have giant Robots that can pick up a supertanker and use it as a club.

 

[Crazy Chainsaw]

Works pretty well in Hollywood, they have giant Robots that can pick up a supertanker and use it as a club.

Hopefully the Time FF has spent here in the last day or so will be (Transformational) to his understanding of physics.

 

[PhantomWolf]

Hopefully the Time FF has spent here in the last day or so will be (Transformational) to his understanding of physics.

I wouldn't be too sure about that. I think Michael Bay has a better grasp of physics.

 

[jaydeehess]

The "speeding up" case (positive acceleration and positive velocity) corresponds to the brick-through-tissue scenario, since everyone's agreed that down = positive.

Yes, I know. I didn't even need my physics degree for that. In our toy scenario of brick-falling-through-tissue, the net acceleration always has the same sign as the velocity. That's what Redwood, myself, and others have been telling you.

That image shows three cases: a uniform acceleration down a slope, a change of direction around a curve (with additional downward acceleration from the gravitational force), and a deceleration purely due to friction force. But an object does not necessarily slow down when the acceleration changes. It doesn't in the brick-through-tissue case, since the acceleration never becomes negative.

Yes, I said that. The brick experiences a small negative force from the tissue, which is much smaller in magnitude than the gravitational force acting on the brick.

The small negative force imparted by the tissue reduces the net positive force acting on the brick, which means that the acceleration changes "only for an instant". During that very short "instant", the velocity continues to increase, just not quite as fast as before the brick hits the tissue. That does not mean it slows down.

What is correct is to say that at a given time after the impact, the [ETA: magnitude of the] velocity of the brick will be very slightly less than what it would have been if no tissue had been there.

I understand this perfectly. I told you that. The brick is accelerating before the impact. The brick is accelerating during the impact. The brick is accelerating after the impact.

You seem to think, as far as I can tell, that the brick somehow decelerates (loses forward speed) during the impact. Remember how, last time I asked you how you validated your application of "basic physics" to complex collapse problems, that I assumed for the sake of argument that you had verified your "basic knowledge" first?

It appears you did not do that. If you think that the brick actually decelerates in our toy scenario, you literally do not understand mechanics at the 8th-grade level.

Very nice.

I learned this level of physics when I was 17 years old. You got it in grade 8! No wonder I was bored a lot in school.

The only thing I would add is that of scaling. Adjusting any one parameter changes the scale. As I said, bring the distance between tissues down to close to zero, and use a whole ream of papers (500 sheets), and the brick will not make it past first impact.

So, two experiments,
1) papers separated by a distance through which the brick can accelerate enough between them to pass through subsequent papers and the brick passes through all of them,
2) papers at near zero separation. Simply a different scale of the same experiment. Brick stops at first impact.

These are lower and an upper case (increasing separation beyond that in 1 will in no way change the outcome) and implies that by altering the one parameter, separation, one could design it so that the brick gets stopped by any number between 1 & 499 impacts.

According to Cole's (and subsequently, FF's) interpretation of Newton, this is not possible. Experiment demonstrates it is possible, ,,, , experiment disproves the hypothesis.