General > General Technical Chat
Mess with your minds: A wind powered craft going faster than a tail wind speed.
IanB:
--- Quote from: IanB on August 30, 2021, 07:37:52 pm ---Unfortunately, if we show you the experiment where the cart in your diagram moves from left to right, you will dispute that too, and will claim that experiment also is being misinterpreted. So it's not worth our time showing you results that you will refuse to believe.
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--- Quote from: ejeffrey on August 31, 2021, 04:15:23 am ---Here you go.
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--- Quote from: electrodacus on August 31, 2021, 04:23:00 am ---Sorry a piece of paper is not a treadmill but you can build a simple treadmill made of paper.
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Prediction fulfilled.
We can be quite clear at this point that we are being trolled.
ejeffrey:
--- Quote from: electrodacus on August 31, 2021, 04:23:00 am ---Sorry a piece of paper is not a treadmill but you can build a simple treadmill made of paper. The paper will need to be glued in a loop and then use two cylinders with axis fixed to the table.
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Oh for fucks sake. It is exactly the same. As we all predicted, I did your experiment and you don't care.
--- Quote ---The reason the piece of paper is not a treadmill is because the paper moves relative to the ground/table where a treadmill will not do that. It is like powering OFF a treadmill and push it under the vehicle.
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The vehicle doesn't care care what is going on with the rest of the treadmill except at the point of contact. The paper is moving exactly the same way as the top surface of a treadmill would. Whether the end returns to the beginning in a loop or whether the paper is supported by another object that doesn't move is completely irrelevant.
--- Quote ---The paper will not push against the generator wheels it will just slide under
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I am literally looking at it right now and the "generator" wheel has good traction and is not sliding against the paper. It is rolling exactly as it would on a "treadmill". I can feel that the paper is pushing on the wheels. If I push too fast, or if I change the gear ratio by using a different pulley it will slip and I can tell the difference.
Listen, despite your obstinance I have tried to take your arguments as in good faith if misguided and frustrating. This is despite all evidence that you are interested in good faith discussion. I did your experiment. It performed exactly as I, and anyone else who can work out freshman physics problems knew would happen, and exactly in accordance with actual mechanics rather that your made up rules that don't exist in any textbook like vector kinetic energy. Yet you continue to be a troll. Go do it yourself, read a book, take a class, or actually try to calculate something.
bdunham7:
--- Quote from: Brumby on August 31, 2021, 04:45:34 am ---Your wheels argument does not reflect the real world environment governing the blackbird AT ALL.
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Wait a second! The wheeled models are demonstrating a principle, they don't have to cover all aspects of the real world operation of the original vehicle in question. The fact that we can't agree on the basic principle of how forces can be made to operate given two mediums/objects/surfaces/whatever moving relative to one another makes it pointless to continue on further to discuss the full vehicle. Sort of like if we can't agree on how levers work, there's no point in discussing gears.
bdunham7:
--- Quote from: ejeffrey on August 31, 2021, 04:49:23 am ---The vehicle doesn't care care what is going on with the rest of the treadmill except at the point of contact. The paper is moving exactly the same way as the top surface of a treadmill would. Whether the end returns to the beginning in a loop or whether the paper is supported by another object that doesn't move is completely irrelevant.
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I proposed just using a block of wood (or paper) earlier as it seemed obvious that it would be providing the exact same moving surface as a treadmill. However, his concept of energy transfer apparently means that they are different somehow and he did raise the same objection at the time.
Brumby:
:palm: Do I really want to try......
Meh. Here goes...................
I will follow on from this excellent suggestion...
--- Quote from: bdunham7 on August 30, 2021, 04:01:24 pm ---Simplifying the the problem to take out some of the variables is usually good way to work past such errors.
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To begin the conversation, let us take an 'ideal' situation (we can add in losses later for practical results).
Using the treadmill example as used in the Veritasium video, let us use a model with the propeller replaced with a stationary flat disc and there being no drive train from the wheels to the disc. The air is still and the belt is moving. We then place this model on the belt so that it rolls along the belt surface, but stays stationary with respect to the floor below (and, hence, stationary with respect to the air).
Proposition: I maintain that, in an ideal situation where we ignore friction and other losses, the belt will continue to move under the model, but the model will remain in the same position relative to the rest of the environment.
Question: Do you agree?
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