Split Thread The validity of classical physics (split from: DWFTTW)

[John Freestone]

I'm going to guess the "C" key. Silly bunt.

I think you should tear off one new key each day, and see how long we can continue to follow your posts. Then once we can no longer understand you, it'll be interesting to see if humber begins to.

Oh mi Bod, that made mi dai! Bood idea.

This keiboard was actualli a cheap one, and it's done me well for several iears. I've tried a restart, but to no avail. (The B hasn't realli bone iet, I just thought I'd bive it a bo to see what kind of bame this would make. Still bet me so far?)

It's excruciating. I'll have to get mi old one out the attic.

 

[spork]

Still bet me so far?

5 x 5 (that's ham geek for "loud and clear")

 

[Clive]

I will look at you boundary answer later today, Clive,

Great. Looking forward to your response.

But please also note that I've just noticed an error in my written description of the boundary layer movement for the treadmill case, and it's too late for me to correct the original post now. I say it is being "dragged" to the left at 2 m/s by the belt. There's no problem with 'it is being "dragged" to the left' (by the belt), but it is actually moving left at 3 m/s relative to the room/treadmill body/"still air" above boundary layer, etc. The 2 m/s is also relevant but that is actually the difference between the belt speed and boundary layer.

but I have made additions to my reply to JohnF. Perhaps you could take a look?
I think only the stationary on belt is in question.

I will have a look at that.

 

[humber]

You seem to think motion can be defined without including the concept of relative motion. Please tell me how. Otherwise, all motion must actually be more strictly defined as relative motion.

What would that matter? One object is of no concern. Introduce another, then you can have relative motion between the objects. What other than "space" could be the common reference? Velocity is secondary to acceleration.
Acceleration is an absolute for all the purposes of this thread. Absolute acceleration has meaning!
That means that you will always know if it is you or the cart that is moving when on the belt. It isolates specifically you, whereas velocity is common to all objects within an attributed "frame".
If you simply declare that you are on the belt at time T, then the chain of information, the the result of the last acceleration you experienced, ( and so consequent velocity) is broken, The necessary connecting information is ignored, so that the necessary "can't tell rule" can be invoked to say that it could be the cart, (not is by the way).
If events are viewed from their acceleration history, rather than their velocity history, then when on the belt, and under the same rules, you should conclude, that your are at the same velocity as when on the floor.
Objects move incrementally, not in frames, and that "history" tells you it is you not that cart that is moving.

It seems clear that is what you are often doing and it's getting very boring.

No. A dissenter must be a deceiver? I don't question your veracity do I? Yet you do mine quite often. Many of my "mistakes" are in fact the result of that bias, an over eagerness to find deception, where there is none.
I know what I write, Clive. I told you, that I have not changed my mind. You will find me saying that the flow is wrong, the belt is going the wrong way, much earlier in the other thread.

Which digit and what false assumption? The digit I am thinking of is straight up and down, and I don't think there is any false assumption.

The two are not related. That has nothing to do with the boundary layer in question. That they do, is that false assumption, Clive. The treadmill is a real object. It may generate what you may label as being something else, but it also still is a machine. In this example, "Windspeed" is metaphorical, unless you are actually traveling at windspeed. Time cannot be held, so you are not traveling when at the treadmill side.

Actually a number of people apart from you did comment on all of those things.

I commented on those, but they were mostly superficial remarks. No refutation, or how Drela actually contradicts many of the points of view, it assumed he supports. It's in the equations.

Perhaps you just had all those people on "ignore"? The laminar flow thing does have a correct answer, and it is crystal clear, but it's not any of the answers you have given so far.

They are all correct.

Well, perhaps I should say your paddle wheel answer could have been correct but only if you were also walking around the apparatus while you wrote it, so that the CW (clockwise) and CCW (counter-clockwise) parts of it depended on which side you happened to be at that time. If that was the case, you need to give us the details of your movements over that time.

It does not imply that, Clive, but it makes no difference because all frames are equal. The laminar flow from the road is correct from the treadmill side, and that agrees with the belt. It is in exact mimicry of jjcote's example. They are not the same, by some margin.

From treadmill side as an unbiased observer. The floor is a valid "frame"

At cart.
Belt Flow is 6m/s right to left, but the "wind" is 0.
So that's a difference of 6m/s to the left. = (CW) in belt test.

Going with the belt,
"Belt-generated tailwind" ia 10m/s left to right.
Flow is 6m/s right to left.
That's a difference of 4m/s to the right. = (CCW) in belt test

ETA:
OK re the laminar flow. This is more significant than you may think, Clive.

 

[humber]

Is this pertinent?

How do you know when to quit?
How do you know when you've won?

 

[humber]

Do you even understand what I proposed? Based on your response, it seems that you just quick scrolled through it.

Here lemme make it clear in point form:

1) It is clear that everyone here believes that you have some serious flaws in your understanding of basic physics

2) You claim that you do not have any such flaws

3) There is an easy way to resolve this, and we can do so without moving onto "advanced" topics such as boundary issues and cart balance.

4) The way to resolve this is to get you to demonstrate that you have a solid grasp of basic physics

5) This can be done by having you solve a small number of physics questions from a high school examination, and comparing your solutions with the correct solutions.

6) If, as you claim, you have no such flaws, this exercise should take you a matter of minutes, and would go a long way to demonstrating that you do indeed have a solid grasp of the basic issues here

Statistics say that I am likely to be more qualified than you, SD.
The overwhelming bulk of academia says you are wrong.
Drela only tangentially supports your views.
I could certainly set you a test that you would not like...

 

[Clive]

Quitters never win, winners never quit, but those who never win and never quit are idiots.
- Anonymous

They have a contest for best wording, and a prize for anyone that can prove the paranormal, but NOTHING for the hopelessly optimistic!

Didn't I tell you? I'm actually going for the prize of biggest idiot, but I'm a bit worried about the other competitors still in the game. There's at least one "real champion" amongst them and he looks like being a tough nut to crack...

 

[spork]

I commented on those, but they were mostly superficial remarks. No refutation, or how Drela actually contradicts many of the points of view, it assumed he supports. It's in the equations.

I can't decide which is my favorite ploy - ignoring the really inconvenient questions, "answering" them with a question of your own (typically incomprehensible gibberish), or misinterpretting every source so unbelievably badly that you conclude it supports your case. This is clearly why you choose to do your own interpretting rather than enter into an arrangement in which said authority makes the decision as to who is right.

 

[spork]

Statistics say that I am likely to be more qualified than you, SD.

Unfortunately, statistics is yet another field in which you've already demonstrated staggering incompetence.

The overwhelming bulk of academia says you are wrong.

See above.

I could certainly set you a test that you would not like...

On the contrary - you've clearly demonstrated that you could not define a test of any sort - whether SD would like it or not.

 

[humber]

I can't decide which is my favorite ploy - ignoring the really inconvenient questions, "answering" them with a question of your own (typically incomprehensible gibberish), or misinterpretting every source so unbelievably badly that you conclude it supports your case. This is clearly why you choose to do your own interpretting rather than enter into an arrangement in which said authority makes the decision as to who is right.

Put your word where your mouth is,then. Show that my paddle result is wrong.
It is correct.

 

[humber]

Unfortunately, statistics is yet another field in which you've already demonstrated staggering incompetence.

I say your chances of dismissing my boundary claim are zero

See above.

Readily measured.

On the contrary - you've clearly demonstrated that you could not define a test of any sort - whether SD would like it or not.

Difficult to test the untestable. The treadmill's results all converge to zero.
Zero displacement, zero KE, zero velocity and zero work. Perhaps you would like to propose a test.?

 

[Christian Klippel]

Unfortunateli, that seems to be for parapsichological frauds - not realli that much to do with humber. Guess which kei on mi keiboard has just stopped working, guis. Ies, iou guessed it. Bie for now.

Hello John,

you might take a look at these beautiful IBM Model-M keyboards. These clicky things.

Not the cheapest ones (albeit not expensive anyways). But i tell you, they last virtually forever. I would never ever use anything else again. Almost indestructible. And with the weight they have you really have something to throw at people

Oh, and the cable is detachable and quite long.

Greetings,

Chris

 

[John Freestone]

Well, at least we got some understanding there, humber. I'm afraid it lost me later. I'm sorry this is so long, and I keep losing my 'y'. I've tried putting them back, but might have missed some. It feels like we might yet solve this boundary layer thing, but I'm not holding my breath!

Yes 4m/s CW. Stand in front of the treadmill as is conventional. Belt moves right to left.

Of course, I see. I never bought into that convention. There are videos and diagrams with things going every which way, so I didn't understand your convention. I guessed right about the method of calculation of the 'rotation'. Excellent.

That is correct. The tailwind that pushing the cart (the real world analogue) comes from the left (South in jjcote's case)

Amazed. You said 'That is correct'!

The information is there, John. CW/CCW are correct. The motion is relative, so make a choice if you don't like that one, but be consistent.

Well, as you now understand, the information about which side you were on was not specified, but assumed. Not a convention I joined up to.

Held when stationary w.r.t the ground, yields the same when held moving from a cart. (real wind)

You seem to have jumped ahead. This came from you saying 'same from windspeed'. I thought this was the 'real wind' situation, and you were holding the device while travelling forward at windspeed. Not stationary with respect to ground, therefore. And stationary w.r.t. ground does not yield the same as when held moving from cart (real wind), unless the device somehow measures relative velocities with respect to objects it has no direct knowledge of. Moving in the air at windspeed, if it acts like an anemometer, it measures 0, not 10, as I stated.

Wind - flow = constant, so (Wind + x) - (flow + x) = constant.

That makes sense, if 'flow' means boundary layer flow.

The difference in velocity of the flows is constant, so the paddle wheel will be constant.

Indeed.

You do not appear to understand your own ideas, here. I choose the belt to meet that expectation. Not even smoke!
It works from all "frames" of course, because all frames are equivalent.

Our point rather than yours, I thought.

There is, nor can there be, a difference.

Missing 'not'? There is not, nor can there be, a difference. Agreed.

The difference in velocity of the real flows is constant, so the paddle wheel will be constant.

Indeed.

Superposition says so.

I'd have to check what that is. Common sense sais so. Math sais so.

Guaranteed to lead to error, time after time. And again. This question I raised months ago. He's wrong (shrug), No, you are all wrong, again.

Well we'll just have to agree to disagree then. I urge ou to think about it again, though. If on the cart on treadmill, with the belt moving backwards at 10, the boundari laier seems to be the contentious issue again. Jjcote said that on the ground scenario, the slice of air we were using went slower than the maximum flow, at 6 m/s, instead of 10.

Ok, here's another way to demonstrate my thinking: Wherever those slices of wind are, we agree the relative velocity is the same between them. It's 10 max, 6 at the boundary layer that we're interested in. Difference 4. So, if we are on the cart on a treadmill, at 'windspeed' (even if I let you have that as not a real wind), i.e. 0, then the calculation given above gives the same as I get. 10 - 10 = 0 (i.e. we are keeping up with the wind, ok), so at the boundary layer (BL from now on), it's 6 - 10 = -4. Hence your own formula also gives the BL at -4 relative to us, i.e. backwards at 4 m/s. As I then punched these numbers into the paddle before, we get 0 (top) - -4 (lower) = 4 m/s "CW".

He can mean what he likes. The belt moves with the belt, so the flow moves with the belt,

Sure it does. But 'moves with the belt' is a biased viewpoint. When the wind blows over the land, the 'flow moves with the land' - we don't normalli express it that wai, we sai it is slowed down bi the land instead, BUT THESE ARE JUST DESCRIPTIONS DEPENDENT ON OUR FRAME OF REFERENCE! If it seems right that the land slows down the wind, not the 'flow' moves with the land, just remember the earth spinning scenario. The air can be motionless w.r.t. the earth, and the land moving under it. We experience that as REAL WIND, and it is SLOWED at the BL.

<snip>

It moves 4m/s CCW. (10 - 6. ) If both flows are 10m/s, no motion. If the bottom flow were slightly faster, which way? CW. If slower = CCW. Simple.

This is for going with the belt? So I agree we have 10 m/s on our backs, 6 m/s on our knees or wherever. This is exactli what we had when standing on the ground in 'real wind'. How come that was CW, and this is CCW? Wind and 'flow' are going left to right w.r.t us. If we face forward, they're still on our backs as they were on the ground. Stand to right of cart in 'real wind' as it races past. Someone standing on the ground, facing the way the cart goes, has wind on back - well, we already did that one. Please, how did you still manage to reverse the sense of that to CCW? In the face of all comers. All of physics would agree with me. Each person, with their eyes closed, can't tell the difference. Suddenly we're supposed to have the paddle going the other way because we've put the thing on a treadmill. Amazed.

Top gets 10 from rear, the bottom (greek....) blade, gets only 6m/s from front (belt flow) so motion = 4 CCW. From cart at windspeed, 6ms CW.

Oh crap, this looks like it's when moving with belt. That would make your numbers for the above even worse, if they were for the cart perspective. Oh well. Apply earlier argument here instead! Look, I agree with the 10 from rear, but you can NOT HAVE THE LOWER AS 6 m/s from the FRONT!

Is this actually it? Is this your contention? That if we blow air over a surface, it has a gradient from positive max to positive minimum, but if we move a surface past a mass of air, its flow is reversed at some point down the gradient? That is what you have described, 10 from rear at the top (because we're ploughing into it with our backs), 6 from front lower down?! What physical effect could possibly cause the wind near the ground (sorry, belt) to reverse direction? No, our knees are also ploughing into the stationary air in the room, except it's not quite stationary. It is moved backwards, as you agree, by the belt (Backwards, that is w.r.t. the room). Hence, our knees plough into it while it is not quite stationary, and feel a 6 m/s worth of cooling effect, a flow from the rear. How pleasant (until we fall off onto the carpet). How can we possibly be moved backwards by standing on a belt, fall off the back, and report that while we did that, our knees had a wind on them from the front? Please try to understand this point: yes, from the room's perspective, the boundary layer is dragged with the belt. From our perspective when standing on the belt going backwards, we are still ploughing through it backwards. The belt doesn't speed it up to belt speed at that height (I'm calling knee height). It speeds it up to belt speed right at the belt level, so the soles of our shoes feel no wind. Everywhere above that, we feel a wind on our backs. I FEEL UTTERLY SURE THAT NO-ONE CAN POSSIBLY READ THAT, WITH A LITTLE PATIENCE AND CONCENTRATION, AND NOT SEE IT. IF I'M WRONG, PLEASE TELL ME HOW YOU CAN BE WHIZZED OFF A TREADMILL BACKWARDS AND FEEL THE WIND ON YOUR FRONT AT ANY HEIGHT. SERIOUSLY. LET'S HAVE THIS ENDED FOR CHRIST'S SAKE.

No. Try again. Back to the drawing board.

I'll remind you that this is the normal physics drawing board. Yours is the screwy one. Tri again. Iou'll get it eventualli.

(1) Real wind = constant difference.
(2) Stationary and windspeed on belt opposite rotations.

Stationary and windspeed? Stationary w.r.t. the room? That is windspeed. You really would make a lot more progress if you remember every time you express a velocity, it needs a w.r.t. something (stated, or clearly implied). "Stationary" means nothing.

(3) Motion up belt can stop paddle at some point (4ms up the belt in this case) Never in wind.

Sorry, I still don't understand this point at all, but it seems wrong if it means accelerating to what we would consider faster than windspeed, and continuing beyond - like if there were miles of treadmill ahead. As we go faster, the difference between the wind max and the boundary layer remains the same. How can it get to zero, so as to stop the paddle rotation, without it actually changing its gradient? There is still belt having an effect on the air, and air at a greater remove that isn't being affected, even if you don't agree what the gradient is. If that were true, why wouldn't the real wind gradient change as we drove faster? Maybe I misunderstood what you're saying there.

 

[spork]

Put your word where your mouth is,then. Show that my paddle result is wrong.

As near as I can tell, no one has a clue what you're even talking about regarding this "paddle".

I say your chances of dismissing my boundary claim are zero

You don't even make a claim. You simply say things like "use red and blue smoke and the answer will be obvious".

The treadmill's results all converge to zero.

Would it seem too redundant for me to point out you're wrong again?

Perhaps you would like to propose a test.?

We've proposed many. Among them - what does 2 + 2 give you? Can you answer some basic physics questions from a 1st year physics text?

 

[Brian-M]

BTW, has humber answered my questions about equivalency? That would almost be worth taking him off ignore to see.

Not that I've noticed. Or at least, not in any way that I could concieve as a coherent answer. He still hasn't answered my skateboarder question yet either.

 

[spork]

Hey guys - I had a thought (don't look so surprised)....

Speak up if you're willing to answer some questions from a basic physics text. I'll go first. I am willing. Who else is game? (and who is not?)

Willing to answer some basic physics questions:

spork: yes
Clive: ?
Christian: ?
humber: ?
Brian-M: ?
John Freestone: ?
JB: ?
fredriks: ?
spacediver: ?
subduction zone: ?
jjcote: ?
sol invictus: ?
H'ethetheth: ?
CORed: ?
Mender: ?

others:?

 

[Clive]

Speak up if you're willing to answer some questions from a basic physics text. I'll go first. I am willing. Who else is game? (and who is not?)

Willing to answer some basic physics questions:

spork: yes
Clive: yes
Christian: ?
humber: ?
Brian-M: ?
John Freestone: ?
JB: ?
fredriks: ?
spacediver: ?
subduction zone: ?
jjcote: ?
sol invictus: ?
H'ethetheth: ?
CORed: ?
Mender: ?

others:?

Yep, I'll play this game also. I'm assuming we're talking mechanics primarily.

 

[mender]

Oh. Now I see what I've been doing wrong! Wow. How could I have been so dense! You guys were right all along and I was so caught up in my justifications of why I mistakenly thought the cart couldn't go faster than the windspeed that I didn't bother to even consider that I might be wrong.

I have this problem understanding what people are writing when they start off with "you're wrong". I somehow get that mixed up because that was the last thing I said to them, and for them to say that is confirmation that I was right all along.

Thanks to everyone for helping me to get this right - finally! I apologize for being so stubborn and dismissing all your excellent explanations as insignificant and beneath me. It really wasn't a smart thing to do but I'm over it now.

Let me know when you're going to do more treadmill tests so I can contribute as well!

I can't tell you how long I've been waiting to read this, humber! Congratulations on your break through.

All the rest of you can take humber off fast ignore now, the game he was playing has come to an end! We can all move on to more fruitful endeavors now!

ETA: Hey! Where did your post go?

Was I the only one to see it?

 

[mender]

Willing to answer some basic physics questions:

spork: yes
Clive: yes
Mender: yes
Christian: ?
humber: ?
Brian-M: ?
John Freestone: ?
JB: ?
fredriks: ?
spacediver: ?
subduction zone: ?
jjcote: ?
sol invictus: ?
H'ethetheth: ?
CORed: ?

Spork, I'm in and the answer is 4!

Did I win?

Okay, I'll wait for the question instead - but I wanted to try just in case.

 

[John Freestone]

Ok, just really quickly this time on this bit again:

At cart.
Belt Flow is 6m/s right to left, but the "wind" is 0.
So that's a difference of 6m/s to the left. = (CW) in belt test.

No. Belt flow is 4 m/s right to left = 4 m/s CW.

Going with the belt,
"Belt-generated tailwind" ia 10m/s left to right.
Flow is 6m/s right to left.
That's a difference of 4m/s to the right. = (CCW) in belt test

No. I'll try a different approach this time: look how you put "belt-generated tailwind" in quotes, because from our usual room-based viewpoint, we can't see any 'real wind'. Right? So what you're correctly doing is giving the velocity w.r.t. the belt. Now, you agreed at one time that things have to be measured from the same frame of reference, for the maths to be correct. Now, the next line, you say the belt flow is 6 m/s right to left. But that is from room perspective. You need its equivalent "belt-generated tailwind", the 'virtual wind' caused by your motion backwards into it, although smaller than the 10. They are 10 and 6, both from rear, just as they are if you stand on the earth in the equivalent conditions with the same 10 m/s wind on your back.

Look, the gradient must be a condition of the friction, so it can't be -10 and - 6 on the earth and then -10 and - 4 on a belt, unless it's a different surface, and it can't be -10 and + 6 without a miracle of a whirlwind. That's like a backwash you've got going on there.

OK re the laminar flow. This is more significant than you may think, Clive.

Going completely the wrong way, you might have a point!