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

[sol invictus]

No, you do it. I want to take it apart.

You've already been told the answer many, many times, but OK: it's identical to the flows in the left panel. a is 10 to the right, b is 9 to the right... h is 1 to the right.

If you give any other answer, it can be easily falsified with smoke. So be very careful....

 

[CORed]

I say that it is negligible, Christian. Of course their is some friction, I have said so many times, but there is little to be overcome in the sense that the cart is driving itself against the belt. It is not, it is just staying in place.

What do the following have in common, Christain. (yes, some have belts);

BMW/F1
A runner's treadmill
An automotive power dyno
An orange spinning on a belt
A cyclist on an exercise bike in a gym
A power station.

What do all of these have in common? They are things Humber doesn't understand. Of course, this is a very incomplete list.

 

[humber]

Ok, I wrote something that should be completely obvious for every one that has seen a river but humber disagrees (as expected)

Read my response before you answer next time. I wrote that the current is less and that it can actually be in the other direction behind an obstacle. Your response is just nonsense.

One problem; it wasn't as you say, and you still managed to support my claims, again.

Or maybe it is because the flow is changed due to the obstacle. Why should a fish have lift by the way.

A simpler explanation. You are wrong.

Go to the nearest river and look at the flow. The flow behind a big rock is simple reversed. The forces depends on the flow.

No big rocks. Stone the size of your hand. and in front of the fish, so reflection is not possible. Got that? Also they do it on smooth beds. Got that?

 

[CORed]

You've already been told the answer many, many times, but OK: it's identical to the flows in the left panel. a is 10 to the right, b is 9 to the right... h is 1 to the right.

If you give any other answer, it can be easily falsified with smoke. So be very careful....

Yes, but if yo do falsify it with smoke, the smoke will be wrong and backwards.

 

[humber]

You've already been told the answer many, many times, but OK: it's identical to the flows in the left panel. a is 10 to the right, b is 9 to the right... h is 1 to the right.

If you give any other answer, it can be easily falsified with smoke. So be very careful....

No, that is observer's inferred motion. Dealt with that months ago. Try direct measurement. If you are right, they will agree.
Let's see you patch over that.

 

[humber]

You are all running around like headless chickens, defending a lame duck idea.
Your skills are woeful! Funny to watch.

 

[fredriks]

Humber have you even seen a river?

 

[John Freestone]

Hey, RossFW, he said

You have an unusual definition of 'ignore'.

Are you going to answer John's question this time, humber?

Maybe he'll ask you to again.

Hello John,

i think that this forum software can't do that, or if, it isn't configured to do so. There is only a "quote" button, and a "reply" button. The latter is just a quick-reply and places you in the quick-reply box at the end of the page, so there is no direct connection to the post one replies to. The quote button embeds the message, but i don't think that it keeps track of a "reply order" either when it is used, it just appears as a regular message. Would be even harder to keep track if multi-quotes are used.

Greetings,

Chris

Thank you Chris. I had a feeling it mustn't be possible. The quote of a message does keep a link to it (the little arrow at the beginning of it), but as you say, it looks like the forum doesn't use that to allow a threaded view. I assume it would be possible, and would have a convention of linking to the first or last in a multi-quote. Cheers anyway. I had a vague feelings I'd done this at one time, but it must have been on another forum.

Was his face on the back of his head?

It's quite useful for calculating or discussing relative velocities and never being wrong to have one on each side, or back and front...basically anywhere just so long as, y'know, you've got two.

 

[CORed]

One problem; it wasn't as you say, and you still managed to support my claims, again.


A simpler explanation. You are wrong.


No big rocks. Stone the size of your hand. and in front of the fish, so reflection is not possible. Got that? Also they do it on smooth beds. Got that?

The current reverses downstream of rocks, even fairly small ones. It's not "reflection". I'm not totally clear on the mechanism, but I know it's there, because I've cast enough flies into such places and watched them drift upstream.

However, I'm sure Humber will have another hilariously wrong explanation.

 

[sol invictus]

No, that is observer's inferred motion.

What does that mean? Inferred how, if not by a measurement of the wind?

Try direct measurement. If you are right, they will agree.

And they do - that is the result of a direct measurement. Given the parameters John set up, those speeds are precisely what an anemometer held at those heights would measure. In reality the variation won't be linear, but it will be monotonic, and (apart from effects due to the finite size of the treadmill, small variations in the wind outside, etc.) will be identical in the two cases.

 

[humber]

Yes, but if yo do falsify it with smoke, the smoke will be wrong and backwards.

You have to use the smoke idea ( my idea of course, in fact they all are) because that is the only hope you have of including your utterly false ideas of "the observer". Straight from the "The Bluffer's Guide to Einstein."

Direct measurement destroys your claim. That's your problem, and you know it.

 

[John Freestone]

No, you do it. I want to take it apart.

Hey, I'm psychic! And then he called you two faced, sol. This is priceless.

 

[Christian Klippel]

However, I'm sure Humber will have another hilariously wrong explanation.

Hello CORed,

the answer should be obvious to you! The fly simply uses the momentum stored in it to slip across the water! Add to that the torsion-spring function of the fishing line and the boundary layer, which we all know flows in the opposite direction, and you get the effect!

Greetings,

Chris

 

[Michael C]

Now, can anyone even fathom what his wrong contention was when he seemed to equate velocity with acceleration?

He's been doing this all along. It's just one of his many confusions: he mixes up force, velocity, acceleration, power or whatever, until nobody has a clue what he means. Here are some quotes from the original DDWFTTW thread to illustrate the velocity/acceleration confusion. I'm not posting them so that Humber can once more try to explain away his mistakes, pretend that he meant something else and say that I'm mis-representing him (although he probably will): I'm posting them for the interest of all those who are trying to understand how he functions. Those who haven't got Humber on ignore can see the original posts in context by clicking on the little arrow next to his name at the beginning of a quote.

A real object's velocity is governed by the power that is available from the source. The gears cannot offer a power gain. Perhaps there will be some change the acceleration, but not the terminal velocity, which will be the same for the same object without gears.

In the Humberverse, the terminal velocity will be "the same for the same object without gears". The whisks on an egg-whisk will turn just as fast without the gearing system. The wheel of a bicycle will turn just as fast if you attach the pedals to it directly instead of using gears. Of course it was pointed out (many times) that Humber was contradicting Newton, and of course Humber always maintained that he wasn't. There was, however, an interesting development that came after Humber had written this:

You can kill my argument dead by showing that you can apply a constant force, and gain an increase in velocity of the cart. Acceleration is always required to keep the gain.
Make graphs of displacement and acceleration and velocity over time. Try and find the sort of pull (constant force, constant velocity. constant power, that will allow you a constant velocity.

It's hard to make complete sense of the above passage, but the gist of it seems to be this: Humber thinks that once you have accelerated, you need a certain force to keep going at the new speed. He talks about a gain in velocity and says acceleration is always required to "keep the gain". He also says you will need some sort of "pull" to allow you a constant velocity. This sentence is especially muddled, since after the word "pull" he puts "constant force, constant velocity. constant power", as if these three terms were all ways to define sorts of "pull", but once again the meaning seems to be that he thinks that a force is needed in order to maintain a constant velocity.

Thabiguy picked on the first sentence of the above quote and Spork proclaimed the news:

Nice catch bigguy!

This just in...

F=MA NO LONGER TRUE

Somehow this managed to get through Humber's defences. I don't know why, since he had been consistently denying that he was contradicting Newton's laws in many other cases where he obviously was. In any case, he must have realised that he had made a blunder and he decided to do something to try to rectify it. He proclaimed that it was a "typo". When pressed by ThinAirDesigns to say exactly what typo could make the sentence correct, he came up with the idea that he had forgotten to type the word "not":

"and not gain an increase in velocity". He would have to falsify F= ma.
Dumbass

I don't know who is meant to be a dumbass, but that's not important. Let's see if we can make sense of the paragraph if we correct Humber's "typo" as he indicates:

You can kill my argument dead by showing that you can apply a constant force, and not gain an increase in velocity of the cart. Acceleration is always required to keep the gain.
Make graphs of displacement and acceleration and velocity over time. Try and find the sort of pull (constant force, constant velocity. constant power, that will allow you a constant velocity.

I can't see how the addition of the word "not" makes sense of this passage. The rest of the passage still claims that a "pull" is required to allow a constant velocity. The confusion between velocity and acceleration is still there. Maybe one of the more creative posters will expose the hidden meaning of this strange paragraph. I leave it as it is: pure Humber in the raw.

 

[H'ethetheth]

I know, but that is not the same as the treadmill. I have answered that in that other post.

It is indeed not exactly the same as the treadmill. It is however in many ways very similar. Especially in cases that were interesting for the design, such as startup and disturbances, where the speed of the water and the walls differ. And like in every wind tunnel, only the relative velocities of fluid and structures determine the forces involved.

You say that you can make comparisons with the treadmill.

Yes, the thing is quite literally a treadmill for fish. I don't see the problem there.

You say I do not understand, on the basis of your authority and experience.

Yes, I can tell that you have trouble to consequently analyse the dynamics of a system from a reference frame not connected to the earth, and worse is that you are unable to accept that you may be wrong about things.

I find that example to be quite erroneous. There are many more disparities than I previously gave. Fish are self-powered, they do not derive their energy from the flow, and so forth.

Changes nothing about the fact that only the relative velocities determine the dynamics if the system.

Next example, please.

Think again. For instance, what propulsive forces would the fish need to generate to rotate at the exact speed of the surrounding water?
What velocities does a fish feel when the wheel starts turning from a standstill?

I would add that your response to my pneumatic boundary generator, if only hypothetical, demonstrates a lack of understanding that many would consider to be independent of education, H'ethetheth.

I didn't respond to your boundary generator, but I remember it was something about pumping air through the surface of the treadmill belt, right? I'd have to check, but that introduces flow that has no equivalent in the real situation, and is therefore wrong.
I'll check it out a litle more accurately later, so correct me if I got your generator wrong.

 

[John Freestone]

No, that is observer's inferred motion. Dealt with that months ago. Try direct measurement. If you are right, they will agree.
Let's see you patch over that.

What is "observer's inferred motion"? Is it the same as observer's experienced motion? How will that differ from observer's direct measurement? Do you mean observer-sitting-by-side-of-treadmill's direct measurement? Do you not think it is possible for us to perform a similar experiment (given a long enough treadmill) and have an actual observer measure those windspeeds at a-h? Can you not imagine such a scenario, just as a thought experiment, and help me, from your esteemed position of knowing the correct answers, by telling me what they would be, if such a thought-experiment person used a thought-experiment anemometer to measure the thought-experiment winds?

I was hoping to go on to more advanced topics, but if I can't get my head round this one (as you said, I got the wrong answers)...oh, please, humber, humour me and tell me what the observer going backwards would measure at a-h?

 

[sol invictus]

The current reverses downstream of rocks, even fairly small ones. It's not "reflection". I'm not totally clear on the mechanism, but I know it's there, because I've cast enough flies into such places and watched them drift upstream.

That's called an eddy. It's usually due to the presence of a vortex - a fairly stable configuration where the water moves in a circular path (a bit like a mini-tornado). There is a "lack" of water behind the rock, since it blocks the current, and so there's a differential pressure that causes the flow on either side to curl in and up.

The same thing happens on a larger scale along the inside of a bend in a river. As any whitewater kayaker knows, those are a great way to get back up-river without much work.

 

[humber]

What does that mean? Inferred how, if not by a measurement of the wind?



And they do - that is the result of a direct measurement. Given the parameters John set up, those speeds are precisely what an anemometer held at those heights would measure. In reality the variation won't be linear, but it will be monotonic, and (apart from effects due to the finite size of the treadmill, small variations in the wind outside, etc.) will be identical in the two cases.

No, that still includes the erroneous use of the observer's motion through the flows. That motion common to both flows, so it drops out of the calculation.

In real wind there is no doubt. The difference is constant, so that blows away your argument concerning linearity or monotonicity, because if present, falsify the treadmill. It is not matter of boundary conditions, because I need not specify the accuracy to anything near that level in order to show the difference. Superposition shows that the two flows can never be reconciled to be the same as one flow, as in real wind. A simple arithmetic fact.

 

[humber]

That's called an eddy. It's usually due to the presence of a vortex - a fairly stable configuration where the water moves in a circular path (a bit like a mini-tornado).

Actually, it's due to a change in impedance caused by the presence of an obstruction.

The same thing happens on a larger scale along the inside of a bend in a river - as any whitewater kayaker knows, those are a great way to get back a little up-river without much work.

For a short time. It is also possible to stay in place, with only but the occasional dip. What do you know, a change of scene, and it's foot-in-mouth time again. Woeful.

The question is only raised because CORed confuses his opinion of what happens, with what actually happens, and confabulates situations to save himself from facing facts that he does not like.

* as any whitewater kayaker knows, a.k.a. not you.

 

[Subduction Zone]

What do the following have in common?

Understanding a problem when written
Proposing a test to investigate the problem
Observing events and interpreting those events correctly
Making diagrams of those events and/or the original problem
Doing simple arithmetic about those events and/or the original problem
Understanding physics about those events and/or the original problem
Answering point blank questions about those events and/or the original problem

Anyone?

Um.. let me give it a shot. They are all things that humber can't do? I am waiting for him to fill in the blanks on Johns illustration, should be interesting.