All quantities are near zero too. KE, velocity, acceleration, displacement, work.
No.
You have zero KE when in your chair, too.
Depends on who you ask.
Math as obfuscation is not the same as math as education, H'ethetheth
OK, please post your analysis of the treadmill. I will address it then.
Math cannot repair a false model, but if you insist.
That's why I asked for assumptions too.
Please explain why it is said, and how it is like the fish tank you said was equivalent. You argued for the belt as evidence of motion. I say it is not needed, so you have now contradicted yourself. All relative quantities are not preserved on the treadmill.
Which interactions are not preserved, humber? Name them.
Please explain how the system can be said to be isolated from the ground ( eg treadmill side) when the system that provides the energy (the motor) is common to ground. The KE of the cart would be from this source, and so measurable from the same ground. To deny that would be to deny the conservation of energy between frames. The KE should therefore appear to all observers.
First of all, KE never appears to all observers.
Secondly, it is not relevant what powers the interaction between air and ground. The interaction is defined only by a difference in velocity.
I say there is a palpable difference between those making motion over the ground, and those buried in it.
Yes. Quite beside the point, however.
They perhaps both experience that same remote force, so that can be ignored as a common factor. How many times are you going to exhume pre-modern ideas? It seems to me that absolutism must be raised so that it can be shot down with what is obvious. Motion is relative. A big discovery apparently missed by all wind-tunnel engineers.
Staggering. Who is raising absolutism here? You can imply that you understand that motion is relative, but this does little to change that most things you say show that you do not.
Have you considered that you may be wrong, H'ethetheth? Your support and replies seem weak and selective.
Yes, for a few seconds, as I was figuring out what to make of spork's demonstration.
Like the cart, the fish has no KE. You agree.
No. Who are you asking?
Yet another false analogy. The runner does the work of moving the limbs and generating muscle force. The object is cardio-muscular exercise, not to emulate motion. The belt passes under the runner's feet, to accommodate human ambulation. ( Essentially we walk by a sequence of free-falls and re-stabilization). This is a fact.
If you like, I could point you to some papers where the researchers did emulate motion with a treadmill. See for instance
here:
You agree. The belt is not necessary, so there can be no frame for the said observer, but wind is, and some of the conditions of travel can be emulated by the motion of a medium. One is enough, and for F1 cars and wind carts, it is the wind. This is contrary to your earlier statement that the wind was not necessary because of the belt. This is essentially the claim of the treadmill. How do you reconcile the lack of wind on the treadmill?
I agree if all interactions are preserved. That is, the wheels should experience a force like that while running over a road, and the air should behave as if it's moving over a road. This can in principle be contrived without a road, or a treadmill, but it is ludicrously difficult, and will never produce better results than a treadmill. So why bother?
No, it is not. They are quite different. The force of the real wind is not self limiting in this way. That is demonstrable. The real wind is not limited by the object that is blown by it. This is not a small difference, but one that the treadmill depends upon. I see no refutation of the self-regulatory mechansim I described. This is a critical difference, that demands more of an answer than the repetition that all is relative.
How is it different? Be specific. Are the propeller blades experiencing different angles of attack? Is the force exerted by the air on the road different? Is the force exerted on the tires by the road different? Name it, and quantify it.
The force of the wind itself does not depend upon gravity, whereas on the treadmill it does.
Wrong. In both cases the force of the wind has nothing to do with gravity. Only the force on the tires depends on gravity.
It is not possible for the force of the wind upon the cart to exceed the demand (load) presented by the cart. One is a reaction to the other. That is not like real wind.
Of course it is, because a gust of wind means an increase in the speed between air and surface. The treadmill equivalent is therefore an increase in treadmill speed.
The real cart's dynamics depend upon the friction to the road, and the dynamic response of the system to perturbation. Without the correct level of KE, or real wind to account for that influence, the dynamics are false. This is why F1 use wind, and you agree that is necessary.
Yes, because 300 kph tailwinds are rare. It is unlikely that Ferrari will want to model this.
No, my analysis stands. The trolley model is equivalent.
What? I agree that it is equivalent. Now tell me how a trolley in still air differs from a treadmill.
This suggests that all KE is that of the observer, and there is none in the cart. No measurement can demonstrate KE for the cart, and that is flat.
This doesn't mean anything. For all observers that report zero KE for the cart, there is an infinite number of observers that will report that the cart is moving. Motion is relative!!! KE depends only on motion, and is therefore also relative! You can keep repeating that I don't know what relative motion means, but it weakens your credibility a bit if you keep saying things like this.
Similarly, to make progress down the belt, the axle must also move w.r.t the belt. When pushed to be seen as going backwards, the wheels should rotate in the opposite direction, but clearly they do not. The wheels spin much as before, in direct opposition to the normal motion of the belt. Motion of a wheeled vehicle in either direction along the belt is NOT possible unless there is contact patch forward of, or to the rear of the axle. On the belt, this contact point is directly in line with the axle because of the fixed relation of belt and wheel. No motion as found on the road, is possible.
I'm sorry, this is gibberish. Give me some numbers, will you?
I believe no such thing, and you know it, whereas you are denying that it can be. It is the equal of all others, and I need not be biased or absolutist to use it. This you also know.
I believe you when you say this. You clearly believe that you don't believe that there is a preferential frame. The thing is, you keep implying there is one. If you wonder where you implied this, go back and find every time someone said to you that motion is relative.
You may believe reiteration to be refutation. In any case, I do not need to assume that the ground is absolute to find fault. I have my trolley equivalent, that allows me to make all claims from that, so the absolutist lament is no longer going to work.
There are enough errors without resort to that claim. anyway.
I'm very happy about your trolley, I honestly am. However, I'm very curious as to the differences between a trolly moving through still air and a conveyor belt moving through still air.
Also in the real world, there are no known examples of objects traveling w.r.t the ground that do not have KE, w.r.t the ground. The treadmill flatly contradicts nature and that is the reference.
The cart has no KE w.r.t. the belt's surface? Tell me, what is the speed of the belt's surface
relative to the cart? Oh, that's right, not zero. What does that tell you about the Kinetic energy?
Put that first point to Steven Hawking. I imagine he can know nothing about anything to do with motion.
No, H'ethetheth. That is not the case. Is there anything that I have written in this post alone that does not fully indicate that I understand that? It is the most basic of ideas. What is there not to understand? I think that I can safely say that I understand that, and its consequences better than you.
Ah, a challenge!
All quantities are near zero too. KE, velocity, acceleration, displacement, work.
You have zero KE when in your chair, too.
All relative quantities are not preserved on the treadmill.
The KE should therefore appear to all observers.
Like the cart, the fish has no KE.
The object is cardio-muscular exercise, not to emulate motion. The belt passes under the runner's feet, to accommodate human ambulation.
The belt is not necessary, so there can be no frame for the said observer, but wind is, and some of the conditions of travel can be emulated by the motion of a medium. One is enough, and for F1 cars and wind carts, it is the wind. This is contrary to your earlier statement that the wind was not necessary because of the belt. This is essentially the claim of the treadmill. How do you reconcile the lack of wind on the treadmill?
The force of the real wind is not self limiting in this way. That is demonstrable. The real wind is not limited by the object that is blown by it. This is not a small difference, but one that the treadmill depends upon.
It is not possible for the force of the wind upon the cart to exceed the demand (load) presented by the cart. One is a reaction to the other. That is not like real wind.
The latter appears in all frames, meaning that it is displacement and not velocity increase. It has essentially no motion.
If an observer stands on the belt, he will move relative to the cart, but that is because he is being accelerated by the trolley, but the cart is not.
Though this one is getting close to being correct. Perhaps a short hint about observers: they're not usually thought of as being massive. They don't do kinetic energy; they represent a vantage point, no more.
Moving on:
No measurement can demonstrate KE for the cart, and that is flat.
Similarly, to make progress down the belt, the axle must also move w.r.t the belt. When pushed to be seen as going backwards, the wheels should rotate in the opposite direction, but clearly they do not.
A runner's treadmill is not the treadmill, nor your fish tank. There is work done, but no linear motion.
"Velocity is relative" is only one aspect of the fact that "All motion is relative".
There, 15 things that you could not possibly have said if you understood that motion is relative.
And I've left out the instances where you flatly stated that the treadmill is not equivalent to a road in wind, because that is the matter at hand. It would be silly to count those.
But, there is light at the end of the tunnel. I can honestly say that I am glad we agree on this:
The trolley model is equivalent. I can easily do more measurements than on the current treadmill. The cart will remain essentially stationary w.r.t the ground. The trolley will pass under the cart so to speak, as its wheels turn.
Handy dandy little paddle device that somehow tells if you are in a real wind or not extra.