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

[jjcote]

Oooh, no, JJcote, you are using the apparent closing distance, but ignoring the direction.

You said you wanted to talk about smoke, so I talked about smoke. I gave a correct description of what will happen with smoke, and you counter not by pointing out some flaw in my smoke narrative, but by switching to a "paddle device" that you have not defined*. Return to the smoke. My description is correct. If you disagree, state what is is that you do not understand.

*I'll happily take you on in canoes with my carbon-fiber Zaveral paddle against whatever you have, though I suppose you'll be at a disadvantage since your canoe generates a bow wave when it isn't even moving through the water.

 

[Subduction Zone]

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.

It must have something to do with the time of year. I just replaced my keyboard after dropping it or kicking the cord one time too many. I bought the cheapest keyboard they had at $20.00 and it is better than my original keyboard. With over 120 keys on it that's about 17 cents a key. I marvel at how cheap electronic goods are.

 

[Clive]

What more is there to say?

You still have it wrong Humber. John Freestone has explained the problems with your paddle wheel post. The whole business has been explained to you (starting nearly 1000 posts ago) in so many different ways by so many different people that it seems there are no words that will ever get through to you. So I'm going to add some "pictures" to the mix in the faint hope that might help in some way.

What you see a little further down in this post represents three snapshots from an animation of firstly the "real wind" blowing over "real ground", and then secondly another three snapshots from an animation showing the "equivalent" treadmill belt and air above it. Note that that should be displayed in a fixed width font (e.g. courier) so that each block of three lines (two mainly filled with hyphens and then the third being the repeating digits with one embedded equals sign) represents one picture, and the lines appear with equal width on your screen.

In each snapshot, the first line represents the air well above any boundary layer effect. This line has a single asterisk in it that represents a marker of some kind so we can follow its motion. The second line in each snapshot represents a layer within the boundary region and uses a plus sign as the marker for some small part of that flow. The third line represents the surface (ground or belt). It is marked with repeating sequence of digits 0-9, but also has fixed reference point marked with an equals sign. Above each snapshot we have the time in seconds after the starting point. I'm also treating the distance from one character position to the next in each row as representing a horizontal distance of 1 metre.

The "real wind" and belt speed is 5 m/s, while our chosen boundary layer moves at 2 m/s relative to the surface that it is moving over, or being dragged by, depending on your point of view.

So, in the "real world" snapshots, we see the air moving left to right above the stationary ground below. In the treadmill snapshots the belt is moving right to left. The upper layer of air is at rest in our "picture frame", and the boundary layer is being "dragged" to the left at 2 m/s by the belt underneath it (moving left at 5 m/s).

"Real wind"/"Real Ground"

Time=0
----------*-------------------
----------+-------------------
0123456789=1234567890123456789

Time=1
---------------*--------------
------------+-----------------
0123456789=1234567890123456789

Time=2
--------------------*---------
--------------+---------------
0123456789=1234567890123456789


Treadmill Wind/Belt

Time=0
----------*-------------------
----------+-------------------
0123456789=1234567890123456789

Time=1
----------*-------------------
-------+----------------------
56789=123456789012345678901234

Time=2
----------*-------------------
----+-------------------------
=12345678901234567890123456789


Does this all make sense to you Humber? Do I need to clarify any part of it?

After I get confirmation that you understand these diagrams and also agree they are a fair and reasonable representation of the situation in each case then perhaps we can move on to address any outstanding issues with paddle wheels embedded in the flow, coloured smoke, things moving in wrong directions, and so on.

 

[humber]

Very definite that is ... one way or the other ... What a nonsense.

Edit: It's definitely raining outside or sunny.

Or cloudy. Next. That's no answer is it?

 

[humber]

A little more patience, and you might get one puzzle right this year.
Ok here goes for the paddle question. I don't know what the 'paddle' is really about, but it seems some device for measuring two air velocities, from which we can calculate the difference.

Good, just like the conclusion.

First of all, it seems right up to '4 m/s', for someone 'standing in real wind', if that means someone standing on the ground. Yes. The top layer is going 10, the particular layer lower down that we're measuring the other velocity of, jj said was going slower, at 6. Difference = 4. Now, I don't get why you've put CW. You're obsessed with clocks.

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

All I can imagine is that if I stood to the East of the 'paddle', the top layer would be going 4 m/s faster than the lower layer, and we can imagine that would spin a 'paddle device' clockwise as we look at it. Yes? I think jjcote's wind direction was from the south, but I can't be sure now.

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

I'll say that was it anyway for this. As I've pointed out before to you, CW and CCW don't mean diddly unless you give enough information.

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.

If we stood to the West of the device, the southerly wind would still be faster at the top layer and slower in the lower layer, but now it would move the paddle CCW. It hasn't changed direction. You just looked at it from the other side. Ok so far. 4 CW looking from the east side.
But now you say same again at windspeed. If you mean we are now travelling with the wind holding the device, you must surely realise that it can only measure the relative windspeed (by now, surely, can't you, by now, surely, please?). So it's top measuring device gets 0 m/s and its lower one gets

Held when stationary w.r.t the ground, yields the same when held moving from a cart. (real wind)
Wind - flow = constant, so (Wind + x) - (flow + x) = constant.

(the speed of the wind jj said it had relative to the ground) minus (whatever speed we are going at)
= 6 - 10
= -4
i.e. the bottom measurer is getting a backwards wind (it's going slower than us at our 10 m/s) of 4 m/s. The top one is stationary. So your bit in brackets should read (0 - - 4 = 4) not (10 - 6 = 4).

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

So when we are travelling with the wind at windspeed, we get: 4 CW looking from the east side. Gosh, that's the same as above. How amazing. A difference in two velocities is the same even when we measure it relative to a different 'ground-zero'. [ETA: I removed one particularly bitchy bit here, because you did get the same answer, and I was criticising the wrong thing, perhaps. The error seems just that you have a magical paddle device that can measure the windspeed relative to the ground when you're travelling at windspeed, rather than reading 0, and the boundary layer w.r.t. the ground (6) instead of w.r.t. the device (-4), but 10-6 does = 0--4 anyway).]

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. There is, nor can there be, a difference.
The difference in velocity of the real flows is constant, so the paddle wheel will be constant.
Superposition says so.

No. The top one is right, 0. The bottom one is wrong. Unfortunately, I'm finding it difficult to think of how to walk you through how to get it right without just employing the relative velocities trick normal people use all the time when doing this kind of thing.

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.

Here goes: JJ said that the boundary layer wind was going at 6 wrt the ground. Now, to any of us, it is obvious that that means that the equivalent layer must also be going at 6 w.r.t. the belt

He can mean what he likes. The belt moves with the belt, so the flow moves with the belt,
from speeds of 0 to 10m/s dependant on height. 6m/s matches jjcote's example.

(or we just haven't got a correct setup and need a wider belt, or the air pressure has changed or something - this depends on such laws of physics - ok?). Therefore, if the belt is going backwards (i.e. negative) 10 and the boundary layer is going +6 with respect to it, then the boundary layer is going -10 +6 with respect to us.

No need to walk, stand fixed to the belt. Attach the paddle by a spindle to the belt to make it easier to see.

= 6 - 10 = -4
So, to correct you above, the paddle will turn (0 - - 4) = 4 CW looking from the east side. Ring any bells?

Only a clanger.
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.

No. Going with the belt, your back is pushed into a wind. That is what you called a positive wind, so you are right to say the top one gets 10. The bottom one is right as well.

Yes. When both lower and upper are in the same velocity flow, no motion.

But where did you get CCW from? The top is still faster than the bottom, and from the rear, just as before. It should therefore be 4 CW looking from the east side. Hmmm.

?

No. JJ said that the boundary layer he was using was going 6 m/s over the ground. In the equivalent scenario, it is also going over the belt at 6 m/s, although from our usual earthbound perspective we might call that the belt going past the wind at -6 m/s.

The belt is the road.

See above calculation. 4 CW looking from the east side.
I think you've even confused the poor wind now.

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.

I have no idea what you mean by that. Wind is the motion of an air mass relative to something else's motion. None of these motions are absolute. Blah blah blah blah...
The answer, in case you missed it, was 4 m/s CW looking from the east side.

No. Try again. Back to the drawing board.

(1) Real wind = constant difference.
(2) Stationary and windspeed on belt opposite rotations.
(3) Motion up belt can stop paddle at some point (4ms up the belt in this case) Never in wind.

 

[Clive]

How can that help? I already fully understand it! It is simply presumed that it is me that is making the mistake. There is no point in going through the motions just for the sake of them.

Why have you spent all this time posting to the threads about the cart Humber?

If you are so sure you fully understand everything, then perhaps you are here to try to correct what you see as other people's mistakes or at least help them understand your perspective. But to do anything like that you have to engage with the other participants in the conversation, try to understand their point of view, and also be willing to explain yours to them. It has to be a two way thing.

This is what I am trying to do with you but instead you play silly games with words and evade the question. Why does this happen most often when you're faced with a particularly difficult situation in terms of maintaining your position? You say you want to sort out the boundary layer issue, so I ask you a question about boundary layers that could be answered with a single digit (stage number). What do I get back from you? Hand waving and excuses. If you aren't willing to engage properly then we might as well all be yelling gibberish at each other. That really would be pointless to me, but perhaps you have a reason for wanting to do something like that? Every time you avoid answering questions it adds to the almost overwhelming impression that you are not being open and honest.

 

[Clive]

Silly bunt.

Spork, is leading letter yellow? "Carts ubiquitously negate treadmills". Abandon All Hope! Ancient code reveals obviously slipping treadmill is Clive's...

 

[spacediver]

Humber, are you willing to accept this challenge?

I've an idea that's less expensive than hiring a recognized expert to read this thread.

Humber, how would you feel if we gave you a few physics questions from an accredited source, and had you answer them. Perhaps from a high school physics exam or something that has good questions on relative motion, windspeed, force, etc.

Then we can compare your answers to the actual correct answers.

Anyone got access to such questions and answers?

 

[humber]

Why have you spent all this time posting to the threads about the cart Humber?

Good question, Clive.
Someone's gotta be somewhere?

If you are so sure you fully understand everything, then perhaps you are here to try to correct what you see as other people's mistakes or at least help them understand your perspective. But to do anything like that you have to engage with the other participants in the conversation, try to understand their point of view, and also be willing to explain yours to them. It has to be a two way thing.

They are ignored on the simple basis that I do not understand. As if.
I post (correct) drawings to receive the same flannel about not understanding the simplest concept of relative motion. The irony is that there is nothing to see. Relative motion is motion unless there is only one object in the Universe. What to do of that? Make a feature of that oddity by creating the non-relative motion of zero KE. You have all 'reversed' nature, so a to make a difference that is not there.

This is what I am trying to do with you but instead you play silly games with words and evade the question.

I like words, but there is no evasion. Why would I bother? Now, if I wanted to to string you along, that would be interesting.

Why does this happen most often when you're faced with a particularly difficult situation in terms of maintaining your position? You say you want to sort out the boundary layer issue, so I ask you a question about boundary layers that could be answered with a single digit (stage number).

The digit was based on a false assumption, Clive.

What do I get back from you? Hand waving and excuses. If you aren't willing to engage properly then we might as well all be yelling gibberish at each other.

Do you think I am yelling gibberish? Do you know how tiresome it is to here "Once gain he displays ignorance of relative motion" I get nothing else at all from some.
Not one of you has commend on Drela's paper, I have and I understand it. Nor of the Russian puzzle, nor of the vector graphs. This laminar wind thing has a definite answer. It is crystal clear.

That really would be pointless to me, but perhaps you have a reason for wanting to do something like that? Every time you avoid answering questions it adds to the almost overwhelming impression that you are not being open and honest.

I never avoid pertinent questions, Clive. Why would it matter it if I were dishonest? Facts are facts. That's why we have science.

 

[humber]

You said you wanted to talk about smoke, so I talked about smoke. I gave a correct description of what will happen with smoke, and you counter not by pointing out some flaw in my smoke narrative, but by switching to a "paddle device" that you have not defined*. Return to the smoke. My description is correct. If you disagree, state what is is that you do not understand.

*I'll happily take you on in canoes with my carbon-fiber Zaveral paddle against whatever you have, though I suppose you'll be at a disadvantage since your canoe generates a bow wave when it isn't even moving through the water.

Both wrong, jjcote.

 

[Clive]

The only thing is that while awarding people stoopid-prizes is fun, I don't think we should encourage that behaviour too much. Your post had too much of the 'round of applause' and 'top marks for persistence' etc. for my liking.

You could be right.

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.

Gosh. Last time it was the "d". But look again, "d" is just above "c". Oh sorry, my mistake, it was only spork picking 'c'.

Never mind... I think I've finally lost it... why?!

 

[humber]

It must have something to do with the time of year. I just replaced my keyboard after dropping it or kicking the cord one time too many. I bought the cheapest keyboard they had at $20.00 and it is better than my original keyboard. With over 120 keys on it that's about 17 cents a key. I marvel at how cheap electronic goods are.

Staggeringly cheap, and they always seem to work. Mouse, $3!
I costed a Chinese consumer audio amplifier. The cost of the parts alone at prices available in Europe, and in big quantities; no development, assembly, packaging, or anything else, was 14% more than the retail price of that device.

 

[humber]

Humber, are you willing to accept this challenge?

I have a suggestion. Correctly solve the boundary puzzle, then the cart balance puzzle. Then we can talk about your understanding, SD.
On that note, experts are not needed. It is not that difficult.

 

[humber]

You could be right.


Gosh. Last time it was the "d". But look again, "d" is just above "c". Oh sorry, my mistake, it was only spork picking 'c'.

Never mind... I think I've finally lost it... why?!

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

 

[Clive]

Relative motion is motion unless there is only one object in the Universe. What to do of that?

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.

Now, if I wanted to to string you along, that would be interesting.

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

The digit was based on a false assumption, Clive.

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.

Not one of you has commend on Drela's paper, I have and I understand it. Nor of the Russian puzzle, nor of the vector graphs. This laminar wind thing has a definite answer. It is crystal clear.

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

 

[spacediver]

I have a suggestion. Correctly solve the boundary puzzle, then the cart balance puzzle. Then we can talk about your understanding, SD.
On that note, experts are not needed. It is not that difficult.

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

 

[fredriks]

I never avoid pertinent questions, Clive.

I have to look up pertinent because I can't make any sense of this when it is written by someone that avoids all questions.

Now I now what pertinent is and the comment is obviously a joke. You sure are funny sometimes humber

So humber why is not the cart on the treadmill evidence that the cart would go downwind faster than the wind? (this must be a pertinent question).

 

[fredriks]

spacediver, basic physics is probably not pertinent to the working of the cart according to humber.

 

[Clive]

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

Is this pertinent?

 

[spork]

After I get confirmation that you understand these diagrams and also agree they are a fair and reasonable representation of the situation in each case then perhaps we can move on to address any outstanding issues...

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

I have a suggestion. Correctly solve the boundary puzzle, then the cart balance puzzle. Then we can talk about your understanding, SD.

Or put more simply - No, you won't try to answer a few basic physics questions. Not terribly surprising really for someone that refuses to take a stance on the "2 + 2 = 4" thing.

experts are not needed. It is not that difficult.

Experts are needed alright - but I don't think it's physics experts you're in need of.