Merged DDWFTTW in a “Real” Wind

[jduffy77]

The example of the tank tells you that it's all a gimmick around wheels
A transform of a runner on the ground: The belt replaces the ground, but the runner is still providing all of the energy. If the belt did that, it would be useless as an exercise machine.

Can the treadmill belt work to drive the tank? Doubtful. How about the runner's feet?
Can't see how. But it can spin a wheel.

Of course it can't spin a wheel, what are you talking about?

 

[Jack by the hedge]

The example of the tank tells you that it's all a gimmick around wheels
A transform of a runner on the ground: The belt replaces the ground, but the runner is still providing all of the energy. If the belt did that, it would be useless as an exercise machine.

Can the treadmill belt work to drive the tank? Doubtful. How about the runner's feet?
Can't see how. But it can spin a wheel.

Nonsense. A tank on a treadmill would stay still if enough force acted to prevent its moving back with the belt. If, for example, some solid object (not on the belt) blocked its path. That example is therefore analogous to the cart. Only the amount of force required to overcome its rolling resistance is different.

 

[CORed]

Nonsense. A tank on a treadmill would stay still if enough force acted to prevent its moving back with the belt. If, for example, some solid object (not on the belt) blocked its path. That example is therefore analogous to the cart. Only the amount of force required to overcome its rolling resistance is different.

The tank would remain still if you fire the tank up and drive it forward at the right speed. This assumes a treadmill big enough and strong enough to run a tank on of course. Your local gym probably doesn't have one.

 

[CORed]

The example of the tank tells you that it's all a gimmick around wheels
A transform of a runner on the ground: The belt replaces the ground, but the runner is still providing all of the energy. If the belt did that, it would be useless as an exercise machine.

Can the treadmill belt work to drive the tank? Doubtful. How about the runner's feet?
Can't see how. But it can spin a wheel.

****in' wheels: How do they ****in' work?

 

[Subduction Zone]

Once again humber you are mistaken about the treadmill. You lost that debate with me over a year ago, but I am willing to reengage you on that issue at any time. You ran away last time, you will probably run away again.

The beauty of the debate is that the questions I asked humber were all yes/no and no math was needed. All he does now is to try to pretend that it never happened.

 

[CORed]

.
There are -no- authorities whose statements may not questioned.
None.
No statement must be accepted solely due to the source.
There must be verifying facts to back any statement up.
Merely "gainsaying"...or as is way too common here, "unequivocal lie" is not a "friendly and lively" way to discuss differences in opinion, which all that is at the base of this long thread.
Facts.
Just the facts.
Real life demonstrations are preferred for physical situations.
Lets see some from all the participants.

You are correct, of course. I was parodying an earlier thread in which humber took me to task for daring to assert that a Ph.D physicist that he claimed supported him was wrong.

ETA: The demonstrations have been done. The DDFTW cart works. One crank refuses to accept the results.

 

[phunk]

Nope. You accept the motion as being with respect to the belt, so the claim sticks. Now you want a ground too?

No, YOU brought the ground into it.

From the point of view of the belt, the cart moves at speed X. From the point of view of the cart, the belt moves at speed -X. There is no difference.

 

[CORed]

And you fell for the cartoon, because it was sold to you in as a math and evidence free gift, but failed to notice that it was repackaged, re-spun, several times along the way.

Lots of evidence has been provided. The "carteers" have provided evidence. You have provided only erroneous math, bizarre misunderstanding of basic physics, incoherent rants, and flatout lies.

You seem to delight in being the only voice crying out against what?

A toy you can't understand being proven to work.

 

[CORed]

Judging by his truthfulness in this debate, I would guess that none of it ever happened.

Good point. I was giving humber the benefit of the doubt, though he really doesn't deserve it.

 

[GlennB]

An obvious discrepancy is the distance covered by the cart with respect to the distance of the belt. Allowing for the notion itself, a (real) car moves as far as the road "moves the other way".

But, the belt is at fixed speed, so if the cart moves along the belt from the "windspeed" state, it is traveling forward further than the belt moves the other way.

My bolding. The belt is at fixed speed relative to the floor of the house. So when you visualise the belt travelling at (say) 8mph that's relative to the floor. This situation has no real-life equivalent as far as an actual lakebed/buggy or road/car is concerned.

So when the cart advances at 1mph up the TM, the relative speeds of cart and belt are, indeed, equal in magnitude. The cart is making 9mph over the belt, and the belt is making 9mph under the cart. No slipping required.

 

[humber]

Do you understand that the cart on a treadmill in still air is intended to model a cart on the ground heading downwind, but from the frame of reference of the air, and not that of the ground or the cart? If you don't realise that then - newsflash - it is. And if you still can't see the relevance of the treadmill test to the cart in the wind then please ask for further explanation.

What about a cart on the table? It has zero velocity relative to the air, but I don't think you would say it was at wind speed. Rest the chassis on some books or whatever, and spin the wheels using an electric drill. Now it is at windspeed? All the TM does is to spin the wheels and prop.

OK. Dimensional analysis aside, it appears now that you see the equivalence.

No. It is not a Galilean Equivalent. Just because that theory is right, does not mean the TM is right. Read up on it. Mechanical equivalence is also a prerequisite. You may be surprised to find that Galileo had some ideas that are now considered to be odd. It is not used much in machines, and is now a matter of philosophy and Relativity.

"It is not generally appreciated, but Galileo made it plain that the reason for the correspondences of observations (in a stationary versus moving shipboard cabin) hinged on the fact that everything in the ship's cabin, especially the air, was moving with the observers.
Regarding these tests Galileo does not mention unaccelerated motion in a straight line. On the First Day discussions he makes it plain that he cannot abide the idea of motion in a straight line. (Straight line travel, according to Salvatius, would soon put the traveler into outer space with no place to go.) It may be said, tongue-in-cheek, that Galileo preferred circular arguments. [Elliptical orbits and oblate spheroids hadn't been invented yet.]"

It is not possible to actually construct a new reality, the TM is a model, not the "same thing".

If your frame of reference is the car then yes, obviously it would remain static from your point of view. But other frames of reference are available. In this case, the still air in the room is your frame of reference. You, the observer, are moving with the wind. Everything else - the cart and the "ground" i.e. the treadmill - move relative to that.
If the cart is travelling faster than the wind and you the observer are travelling at the same speed as the wind then, yes, it does behave exactly like that.

No. The belt is the road. That is; the planet's surface. Imagine that from outer space. The claim becomes that the spinning Earth is driving the cart. That is, it is "dragging it backwards" through the air to create a "virtual tailwind". Nonsense.
The atmosphere moves with the planet. Wind is independent motion of the air, like local stirring. If not, all places would see the same wind as the planet moved under the atmosphere.

Right.Sorry, no, it's not easily perceived. It makes no sense. Are you simply confusing yourself between two different frames of reference - that of the cart and that of the wind?

The TM is a simple machine.
Imagine that a simple wheeled cart is put on the belt. There is good friction, so a drag force of 1N, and the belt drags the cart down the belt. Perhaps over 1/10 second it moves 10mm, and gains KE in the direction of the belt.

But, if the wheel turns, all of the work is done on the wheel, and none on the cart. All of the KE is stored angularly in the rotating components.
It has no KE down the belt.
That is largely how it works. The prop provides a stabilising force. The rest is rather complex detail over short time scales, but the overall effect is that the cart gains no linear KE, and operates at a very low power level, resulting in low friction to the belt. It essentially slides on the belt. There are several means of doing the same thing and they bear no resemblance to a prop cart.

Buy a simple cart like this. Put it in your pocket and experiment at the supermarket checkout. It takes nothing to stop it moving with the belt.
Here is mine. Cost 1 Euro. I already knew the answer, but I tested it to see what I may have missed, and to try to explain it on the forum. None of the Carteers bothered to repeat the test.

 

[humber]

No, YOU brought the ground into it.

From the point of view of the belt, the cart moves at speed X. From the point of view of the cart, the belt moves at speed -X. There is no difference.

You ignored it, and even accepted a cart that was tied to it, so that rather undermines your authority. A lot of the cart is like that: simple, unquestioning acceptance. No amount of exposure of deception, copying or simple lying will, undo the faith. That is the price of laziness.

 

[humber]

Lots of evidence has been provided. The "carteers" have provided evidence. You have provided only erroneous math, bizarre misunderstanding of basic physics, incoherent rants, and flatout lies.

You seem to delight in being the only voice crying out against what?

A toy you can't understand being proven to work.

Not a lone voice, but a persistent one, and no Carteer has ever provided any evidence whatsoever. The theory has changed many times, but Spork is sensitive about being "the creator" so was economical with the truth about adopting Smith's ideas, but the forum history contradicts him.

 

[Modified]

Nope. You accept the motion as being with respect to the belt, so the claim sticks. Now you want a ground too?
What about the "Physics on a Shoestring Video", where the cart is tethered to the frame? What can that be?
A cart on the road, tied to trees on the roadside, as the road moves with respect to the ground.
Galilean equivalency; what a joke.

You're really no good at this. The equivalent would be a cart tethered to a frame which was being towed at wind speed by something that would be largely unaffected by the cart, such as a couple of loaded semi trucks.

What about a cart on the table? It has zero velocity relative to the air, but I don't think you would say it was at wind speed. Rest the chassis on some books or whatever, and spin the wheels using an electric drill. Now it is at windspeed? All the TM does is to spin the wheels and prop.

You can equivalently say that if you drop the cart moving at windspeed on the road, all the road does is to spin the wheels and prop. Yet if you do that with the cart it will accelerate, if you do it with an unpowered car, it will roll to a stop.

 

[phunk]

You ignored it, and even accepted a cart that was tied to it, so that rather undermines your authority. A lot of the cart is like that: simple, unquestioning acceptance. No amount of exposure of deception, copying or simple lying will, undo the faith. That is the price of laziness.

What are you talking about? Tied to what? I wish I knew what the hell you were talking about, but your replies seem to have little to do with the points I was making.

 

[humber]

You're really no good at this. The equivalent would be a cart tethered to a frame which was being towed at wind speed by something that would be largely unaffected by the cart, such as a couple of loaded semi trucks.

And what allows you to assert that? The trees work for me.
And does Galileo allow for mysterious trucks?

You can equivalently say that if you drop the cart moving at windspeed on the road, all the road does is to spin the wheels and prop. Yet if you do that with the cart it will accelerate, if you do it with an unpowered car, it will roll to a stop.

Back to the road driving the wheels, Modified
That was indeed the original claim, but that was a bit too cranky for NASA and others, so the cart got a new lick of paint in the from of the "air lever", which has the wind as the power source.

 

[humber]

What are you talking about? Tied to what? I wish I knew what the hell you were talking about, but your replies seem to have little to do with the points I was making.

Then you have not done your research. The video "Physics on a Shoestring"
The videos are in general, self-injurious. The "Harold Bricer" test shows that the same fan used in "Prop or Turbine" blows the cart off the belt, but at a greater distance. The "Counter Rotation" is a hoot. Not forgetting "Tiny Hands" was made in response to a comment about the size of the operator's hands....

 

[D'rok]

What about a cart on the table? It has zero velocity relative to the air, but I don't think you would say it was at wind speed. Rest the chassis on some books or whatever, and spin the wheels using an electric drill. Now it is at windspeed? All the TM does is to spin the wheels and prop.


No. It is not a Galilean Equivalent. Just because that theory is right, does not mean the TM is right. Read up on it. Mechanical equivalence is also a prerequisite. You may be surprised to find that Galileo had some ideas that are now considered to be odd. It is not used much in machines, and is now a matter of philosophy and Relativity.

"It is not generally appreciated, but Galileo made it plain that the reason for the correspondences of observations (in a stationary versus moving shipboard cabin) hinged on the fact that everything in the ship's cabin, especially the air, was moving with the observers.
Regarding these tests Galileo does not mention unaccelerated motion in a straight line. On the First Day discussions he makes it plain that he cannot abide the idea of motion in a straight line. (Straight line travel, according to Salvatius, would soon put the traveler into outer space with no place to go.) It may be said, tongue-in-cheek, that Galileo preferred circular arguments. [Elliptical orbits and oblate spheroids hadn't been invented yet.]"

It is not possible to actually construct a new reality, the TM is a model, not the "same thing".


No. The belt is the road. That is; the planet's surface. Imagine that from outer space. The claim becomes that the spinning Earth is driving the cart. That is, it is "dragging it backwards" through the air to create a "virtual tailwind". Nonsense.
The atmosphere moves with the planet. Wind is independent motion of the air, like local stirring. If not, all places would see the same wind as the planet moved under the atmosphere.



The TM is a simple machine.
Imagine that a simple wheeled cart is put on the belt. There is good friction, so a drag force of 1N, and the belt drags the cart down the belt. Perhaps over 1/10 second it moves 10mm, and gains KE in the direction of the belt.

But, if the wheel turns, all of the work is done on the wheel, and none on the cart. All of the KE is stored angularly in the rotating components.
It has no KE down the belt.
That is largely how it works. The prop provides a stabilising force. The rest is rather complex detail over short time scales, but the overall effect is that the cart gains no linear KE, and operates at a very low power level, resulting in low friction to the belt. It essentially slides on the belt. There are several means of doing the same thing and they bear no resemblance to a prop cart.

http://www.internationalskeptics.com/forums/attachment.php?attachmentid=21614&stc=1&d=1301505921

Buy a simple cart like this. Put it in your pocket and experiment at the supermarket checkout. It takes nothing to stop it moving with the belt.
Here is mine. Cost 1 Euro. I already knew the answer, but I tested it to see what I may have missed, and to try to explain it on the forum. None of the Carteers bothered to repeat the test.

http://www.internationalskeptics.com/forums/attachment.php?attachmentid=21615&stc=1&d=1301506578

Classic stuff. Absolutely classic.

 

[phunk]

Then you have not done your research. The video "Physics on a Shoestring"
The videos are in general, self-injurious. The "Harold Bricer" test shows that the same fan used in "Prop or Turbine" blows the cart off the belt, but at a greater distance. The "Counter Rotation" is a hoot. Not forgetting "Tiny Hands" was made in response to a comment about the size of the operator's hands....

None of those videos have anything to do with the comments I made that you were responding to. Stop changing the subject.

 

[CORed]

And what allows you to assert that? The trees work for me.

Because the trees would be moving with the belt. You really don't get it at all, do you?

And does Galileo allow for mysterious trucks?


Back to the road driving the wheels, Modified
That was indeed the original claim, but that was a bit too cranky for NASA and others, so the cart got a new lick of paint in the from of the "air lever", which has the wind as the power source.

If you understood frames of reference, you would realize that the only difference between the road as the power source, and the wind as the power source is a change in frames of reference. In general terms, the power source is the difference in velocity between the air and the ground, or, in the case of the treadmill, the air and the belt, aka wind.