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

[sol invictus]

Boats must overcome the drag upon the hull, just as a windblown object must overcome the aerodynamic drag.

Totally wrong. Drag (from the water) only acts if the boat is moving at a different speed than the water it's floating in. Air resistance is the only thing that might make it float slower than the river flows.

The fastest river water is somewhat below the surface. In a canoe you cannot travel as fast as even the surface water without paddling.

Actually the fastest flow is typically at or near the bottom - which means the boat will move faster than the surface water. So you have that exactly backwards, as usual.

But consider a wide river in a smooth, channel, in which case the velocity gradient tends to zero and we can treat the river as if all the water were moving the same speed. Then (neglecting air resistance) the boat will move at exactly the speed of the water unless someone starts to paddle.

Have you ever been in a canoe on a river?

 

[Reality Check]

That would all be useful to know when it can be shown that the treadmill is subject to any of the above effects.

The answer is when we have instruments that can detect gravitational effects of frame-dragging to a precision of parts per trillions.
But this is of course useless for any experiment using the treadmill because the effect is "about one part in a few trillion".

 

[Christian Klippel]

How does a car or house stationary wrt the ground move without accellerating, and so increasing its KE?

How does a bullet or arrow stationary wrt to me move without accellerating, and so increasing its KE?

Or in other words: In the humberverse, is the earth not only the center of the universe, but also stationary relative to it and not spinning, and everything else in it moving around the earth?

 

[humber]

Totally wrong. Drag (from the water) only acts if the boat is moving at a different speed than the water it's floating in. Air resistance is the only thing that might make it float slower than the river flows.

[QUOTE
Actually the fastest flow is typically at or near the bottom - which means the boat will move faster than the surface water. So you have that exactly backwards, as usual.
[/QUOTE]
Incorrect. The drag of the water to bed is greater than that between the water and air. This suggests to the alert mind that the fastest water is probably closer to the surface than the bed. This is indeed the case. The water is fastest at perhaps 1/3 depth, with the velocity slowing as it approaches air or river bed.
The hull of the boat must move the water ahead so that it may occupy that space. That takes work, and more than is available from the water, so a boat will not reach riverspeed in a constant flow, otherwise the river could go faster than itself. Conservation of energy and all that.

But consider a wide river in a smooth, channel, in which case the velocity gradient tends to zero and we can treat the river as if all the water were moving the same speed. Then (neglecting air resistance) the boat will move at exactly the speed of the water unless someone starts to paddle.

No, it is not anywhere close to zero. You generate idealized models to support your contentions, at the expense of accuracy.
The water adjacent to the hull sticks to it just like the laminar flow of the air, so your model is impossible for a second reason.

Have you ever been in a canoe on a river?

I refrained from mentioning that, but since you ask, I have done extended river journeys Australia and South America. Not organized trips, but private adventures. Not before a lot of practice, of course.
Do you ever leave your ivory basement?

 

[humber]

The answer is when we have instruments that can detect gravitational effects of frame-dragging to a precision of parts per trillions.
But this is of course useless for any experiment using the treadmill because the effect is "about one part in a few trillion".

Yes, of course. Frame dragging was a straw man introduced by those who were losing the battle.
The tile of this thread is not appropriate. It should be something like " Is a treadmill an accurate frame of reference?"
The argument is not one of classical versus "equivalence", but science verses woo.

Gaston. Can we change that?

 

[Subduction Zone]

Yes, of course. Frame dragging was a straw man introduced by those who were losing the battle.
The tile of this thread is not appropriate. It should be something like " Is a treadmill an accurate frame of reference?"
The argument is not one of classical versus "equivalence", but science verses woo.

Gaston. Can we change that?

If I remember correctly it was you, humber, that tried in your misunderstanding of physics to introduce frame dragging. In fact early on you were confusing the ideas of "relative velocities" with Einstein's theory of relativity. You don't even have to go to the links, Dan quoted all of the relative text. Or all of the physicists in the world wrong too?

I see that you understand enough high school level physics to get some of the formulas right but you still have to wrap you head around the idea of relative speed and frames of inertia.

 

[Reality Check]

Yes, of course. Frame dragging was a straw man introduced by those who were losing the battle.
The tile of this thread is not appropriate. It should be something like " Is a treadmill an accurate frame of reference?"
The argument is not one of classical versus "equivalence", but science verses woo.

Gaston. Can we change that?

Are you using "frame of reference" as in the scientific definition of a frame of reference?
Or are you using the English meaning which is something like shall we use the treadmill as the basis of the discussion?

 

[sol invictus]

Incorrect. The drag of the water to bed is greater than that between the water and air. This suggests to the alert mind that the fastest water is probably closer to the surface than the bed. This is indeed the case. The water is fastest at perhaps 1/3 depth, with the velocity slowing as it approaches air or river bed.

That's just flat-out wrong. I just pulled up a paper that measured the velocity flow in a gravel-bedded river in two different years, using multiple sensors at many different heights and locations. The results are that the velocity is close to constant, but increases slightly with height above the bottom all the way to the top. In no case is the maximum 1/3 of the way down (it's possible that could happen in certain river sections with a particular width/depth ratio due to edge effects, but if so it would be a special case).

What I said was partially wrong - the flow velocity increases with depth only when the flow is stratified in a certain way, but it turns out the flow in most rivers is turbulent.

The hull of the boat must move the water ahead so that it may occupy that space. That takes work, and more than is available from the water, so a boat will not reach riverspeed in a constant flow, otherwise the river could go faster than itself. Conservation of energy and all that.

Totally and completely wrong. When the boat is moving at riverspeed in a constant flow, the hull moves no water at all, because the water moves with it. How can you possible fail to understand that?

No, it is not anywhere close to zero. You generate idealized models to support your contentions, at the expense of accuracy.

Again, totally wrong. As I said, in a wide river with a smooth bottom the velocity profile is almost perfectly constant. See here for some theory, or the plots in the paper I linked to above. Of course, you've demonstrated over the last 2000+ posts that neither logic, physics, nor empirical data will cause you to budge from your wrong positions.

I refrained from mentioning that, but since you ask, I have done extended river journeys Australia and South America. Not organized trips, but private adventures. Not before a lot of practice, of course.

Stupidity is the inability to learn from experience or explanations.

 

[humber]

How does a bullet or arrow stationary wrt to me move without accellerating, and so increasing its KE?

That's right. Bullet time is 'notional'. No work can ever be done, unless one object does break the "KE = 0" rule. The treadmill 'works' only under that restraint. Do you think that is a realistic proposition?

Or in other words: In the humberverse, is the earth not only the center of the universe, but also stationary relative to it and not spinning, and everything else in it moving around the earth?

You contradict yourself there, Christian. Earlier someone suggested that I may believe the Earth to be the center of the Universe. Why?
It would seem that I must infer that because I see the Sun moving relative to "me". As an "equivalantist" you can also do nothing else, or simply say that "you can't tell".
Only when informed by other means can you say that you are right about your Heliocentric view. Meanwhile, others disregarded what their eyes told them, and reached the correct conclusion from that same earthly perspective.
You can stand on a treadmill and call that a "frame", but you cannot declare it to be stationary, and have the Universe rotate around you.

Nothing wrong with the idea of frames of reference. It is interesting to note that to make a claim for the treadmill, Spork must convince you that "absolutism" is a widely held competing view, and that I must hold to it. But it is not, and I do not. I can't seem to convince you of that.

The mistake is not with science, but the treadmill itself.

 

[John Freestone]

Hey humber - how do you like posting in a special thread created just for you and your trolling, entitled "The validity of classical physics"?

Of course you can't post in the other, since anything you said would be off-topic and a violation of the forum rules. It's a bit like being in prison...

I guess the mods would also split any mention of trolls from here to Forum Management, AHH, as with mention of trolls in the original thread. Hence trolls will continue to troll indefinitely, while the trollees must not respond. I suppose ignoring a troll is the best idea, although it does leave them the option of continuing to troll without responses. Maybe our only hope is that they get bored when their attention-seeking behaviour does not reward them with responses.

I think if it were my forum I would identify trolling behaviour, even if not perfectly, and take measures against the troll. Let's face it, the identification of insulting behaviour is not perfect either. People can get warnings for relatively mild irritation and sarcastic mirth, while at other times they get away with serious and repeated insult.

That's all off topic and mentions trolls, so it will be subject to sanctions, but you started it! This post will self-destruct in...

 

[Christian Klippel]

That's right. Bullet time is 'notional'. No work can ever be done, unless one object does break the "KE = 0" rule. The treadmill 'works' only under that restraint. Do you think that is a realistic proposition?

You contradict yourself there, Christian. Earlier someone suggested that I may believe the Earth to be the center of the Universe. Why?
It would seem that I must infer that because I see the Sun moving relative to "me". As an "equivalantist" you can also do nothing else, or simply say that "you can't tell".

You can not have it both ways. You can not claim that a house not moving relative to the ground has 0 KE, but also say that a bullet that is not moving relative to me still has KE. You asked "where did all the KE go" in the bullet case. Now i look at the earth from some point in space and ask you: where did all the KE of the house go, that it clearly must have, since it is moving relative to me now.

It's more than clear that you try to wiggle yourself out of the many corners you placed yourself in. The earth is nothing special, so it has no special place in physics as the ultimate reference for everything. If you claim that a bullet has KE relative to me when i move at the same direction and speed (and you did that more than once), then it follows that the house i'm in must also have lots of KE relative to me.

You fail to follow your own, borked understandings and explanations. It is you who contradicts every known principle. Many people showed you that already, but you still fail to get it. If you insist on your ground-bound view of everything, then indeed you make the earth the center of everything, including the universe, which is wrong.

The mistake is not with science, but the treadmill itself.

No, the mistake is with your wrong understanding of core principle of physics. But come on, wiggle some some more. It's really fun to watch that. Your buttons are so easy to play. And your responses are just so predictable. That is, they are wrong almost always.

 

[humber]

That's just flat-out wrong. I just pulled up a paper that measured the velocity flow in a gravel-bedded river in two different years, using multiple sensors at many different heights and locations. The results are that the velocity is close to constant, but increases slightly with height above the bottom all the way to the top. In no case is the maximum 1/3 of the way down (it's possible that could happen in certain river sections with a particular width/depth ratio due to edge effects, but if so it would be a special case).

I can find contradictory information. My basic line of reasoning demonstrates that it will generally be so. I did say generally. Of course any particular contrived counter-example can be found. For navigable rivers, my case holds.

What I said was partially wrong - the flow velocity increases with depth only when the flow is stratified in a certain way, but it turns out the flow in most rivers is turbulent.

What you said was wrong, but partially correct.
It is a staw man, and a double one. The analogy was with a flowing navigable river. You can choose white water littered with rocks if you wish, but then you must compare that with the same for air/wind.

Totally and completely wrong. When the boat is moving at riverspeed in a constant flow, the hull moves no water at all, because the water moves with it. How can you possible fail to understand that?

I understand it, if for no other reason than the paper you quoted contradicts your assertion of contiguous flow, and that viscous drag is a reality. I am reminded of that every time I ride my motorbike. Downwind, or not.
ETA:
The image is rather Biblical. A canoe moving down the river, with the water magically parting, yet not moving. The water ahead and behind is also frozen, as it cannot move relative to itself, nor to me. It is as if it were not a river, but a glacier.

Again, totally wrong. As I said, in a wide river with a smooth bottom the velocity profile is almost perfectly constant. See here for some theory, or the plots in the paper I linked to above. Of course, you've demonstrated over the last 2000+ posts that neither logic, physics, nor empirical data will cause you to budge from your wrong positions.

That changes nothing! Where does it say that if a river's cross-section is perfect, that a boat travels at the speed of the water?
You are equivocating over details that do not support your claim.

Stupidity is the inability to learn from experience or explanations.

No, stupidity is the adherence to errors, even at one's own expense. Carry on.
Perhaps there are canoeists who think they can tell the river what to do. They never become very good at it, because they can't read in real time.

 

[humber]

I have no problem with the scientific precept of "equivalent frmes of reference". I have said that the precept is misused to support the idea that the treadmill is a frame of reference equivalent to that of a cart traveling at wind speed.
My over-arching claim is that this is nonsense.
If there can be 'claim to frame' for the treadmill, then it is as if you were standing on a treadmill, and nothing to do with winsdpeed travel.

I did not introduce "frame drag" that was "humb", someone trying to parody me. I then claimed that I was humb to make a mockery of it.

 

[humber]

<snip>

Hopelessly inadequate. I see that the lamb thinks he is now the ram.
"Trolling", as you say, is difficult to define. I don't see that I need to take seriously your second-guessing of this forums' moderators.

 

[humber]

You can not have it both ways. You can not claim that a house not moving relative to the ground has 0 KE, but also say that a bullet that is not moving relative to me still has KE. You asked "where did all the KE go" in the bullet case. Now i look at the earth from some point in space and ask you: where did all the KE of the house go, that it clearly must have, since it is moving relative to me now.

The KE goes with the moving body.

It's more than clear that you try to wiggle yourself out of the many corners you placed yourself in.

The earth is nothing special, so it has no special place in physics as the ultimate reference for everything. If you claim that a bullet has KE relative to me when i move at the same direction and speed (and you did that more than once), then it follows that the house i'm in must also have lots of KE relative to me.

I am in no corner. The earth is special in one respect. That's where you are, and where you evolved. You can maker all of the cartoon physics you wish, but that is not reality. The treadmill is real.

You fail to follow your own, borked understandings and explanations.

Can't stand Bjork

It is you who contradicts every known principle. Many people showed you that already, but you still fail to get it. If you insist on your ground-bound view of everything, then indeed you make the earth the center of everything, including the universe, which is wrong.

No I do not. You refuse to take yes for an answer. You would have done well during the Spanish Inquisition. All that is needed is a confession. A literal word-for-word affirmation. I must first agree with you, before you will argue your claim.

No, the mistake is with your wrong understanding of core principle of physics. But come on, wiggle some some more. It's really fun to watch that. Your buttons are so easy to play. And your responses are just so predictable. That is, they are wrong almost always.

Keep banging in the same drum, so that all else will be unheard.

 

[John Freestone]

You fail to follow your own, borked understandings and explanations. It is you who contradicts every known principle. Many people showed you that already, but you still fail to get it.

Quite right, Chris.

If you insist on your ground-bound view of everything, then indeed you make the earth the center of everything, including the universe, which is wrong.

Not only that, but he can't even deal with the fact that bits of the earth are moving at different speeds relative to each other! What's he gonna choose as ground zero, the centre of the earth, so the poles are still, but the equator is moving at 1000 miles per hour?

No, the mistake is with your wrong understanding of core principle of physics. But come on, wiggle some some more. It's really fun to watch that. Your buttons are so easy to play. And your responses are just so predictable. That is, they are wrong almost always.

Yeah, it was fun. It's beginning to get boring even for me now, and I have quite a high boredom threshold. The trouble is that humber has dredged the bottom of the barrel of stupidity, and nothing would surprise me anymore...well, except for him to say something true and relevant. That would be novel.

 

[humber]

It's beginning to get boring even for me now, and I have quite a high boredom threshold.

Don't spread it so generously.

 

[Subduction Zone]

In one response we see humber claim that he understands frames of reference and then the posts some nonsense like this

The KE goes with the moving body.

No matter how many times he is told or shown by physics links that KE is always a relative property he won't understand and will always insist his silly equivalence to the flat earth belief.

 

[sol invictus]

I can find contradictory information.

Go ahead. I've given you two references, one a detailed exposition of the theory and the other a paper containing measurements on a real (and fully navigable by small boat, according to their description) river.

In response, you just make unsubstantiated claims. We know what those are worth.

My basic line of reasoning demonstrates that it will generally be so. I did say generally. Of course any particular contrived counter-example can be found. For navigable rivers, my case holds.

You gave no reasoning that indicates that. You're wrong.

I understand it, if for no other reason than the paper you quoted contradicts your assertion of contiguous flow, and that viscous drag is a reality.

No, it confirms it. You didn't read it.

That changes nothing! Where does it say that if a river's cross-section is perfect, that a boat travels at the speed of the water?
You are equivocating over details that do not support your claim.

No, I'm proving that what you said was false. Do you now accept that you were wrong?

 

[Dan O.]

Are you using "frame of reference" as in the scientific definition of a frame of reference?
Or are you using the English meaning which is something like shall we use the treadmill as the basis of the discussion?

The discussion in the parent thread was about inertial frames of reference and whether the cart on the treadmill is a valid representation of the cart on a road. I have fixed the tags to reflect that.

In the parent thread, this discussion was leading to bad tempers because it was detracting from what the majority of the participants wanted to discuss. I hope that here it can be properly debated without getting personal.

I specifically left cart and treadmill out of the OP for this split so as not to limit the discussion here to the one case. This thread may go it's own way.