The rug is pulled at constant speed and I'm siting on it and I can just relax. On a treadmill at constant speed I still need to burn plenty of calories.Here is someone standing on a treadmill, feeling very relaxed, and not burning any calories:
https://youtu.be/GvfF4TeXz7UQuoteThere are no weird scenarios is just you(most of you)(all of us) not able to understand there is a big difference between a treadmill and that rug.There, fixed that for you.
The way peoples brain work is very different likely way more different than you imagine. You should search about Aphantaisia that affects maybe 1 to 3% of the population the others have a spectrum of capabilities in creating a mental image. And you should also look-up "Internal monologue" where an estimated 30% of the population has no internal monologue. You will be blown away.
I can create a mental image (sort of average) and I sure have an internal monologue so I think more abstract using language.
I can simulate fairly accurately in my head how a simple cart like those in my diagram will work including what wheel is the generator and witch is the motor and I can know the outcome.
I can also imagine air as a multitude of small particles moving at a relatively constant speed above the ground and that have elastic forces keeping them apart like repelling magnets and then imagine a vehicle driving in the same direction at higher speed than this air molecules and can see that air molecules can no longer help accelerate the vehicle (impossible) but I can also imagine this now higher pressure behind the vehicle meaning higher density (more air particle in the same volume now with higher forces keeping them apart same as force increases when you try to bring two opposing magnets closer).
This is the so called stored energy and as vehicle continues to accelerate this pressure will reduce meaning the density of air molecules drops up to the point that there is not enough pressure to cover the vehicle losses and so vehicle will start to decelerate until it will get below wind speed.
If this description created for you a mental image (visualizing this moving animation) then you will also know vehicle can not be powered by wind when vehicle speed is higher than wind speed in the same direction.
With this mental model of air, what you have been saying about energy storage, and other characteristics of gases, would make some sense.
Unfortunately this is a very poor model for air, or any other gas. For example, the particles in your model appear to only be moving at the speed of the wind, so it is very easy for a vehicle to outrun them. In reality, the molecules of nitrogen, oxygen and other gases that make up the air, are moving randomly and at speeds comparable to and often higher than the speed of sound. There are also no significant forces between the molecules keeping them apart, except briefly when they collide with one another or with other objects.
A far better model is that used in the kinetic theory of gases. The Wikipedia page on this subject includes an animation that may help you to form a much more useful mental image. https://en.wikipedia.org/wiki/Kinetic_theory_of_gases Once you have moved over to using that model, a lot of the things that others on this thread have said should begin to make sense.
I think that your other sources of disagreement with the rest of us may be due to poorly defined frames of reference. In particular, the wrong choice of reference frame can obscure the simple relationships between force, distance and energy or work done. I tried to explore this earlier with my thought experiment with a passenger walking down the aisle of an aircraft.
I have aphantasia myself, so I do have some sympathy with you. I can't form any kind of internal visual images, but I can form what I can best describe as invisible wire-frame images, that I can freely manipulate and rotate. I can't see them in any visual sense, but I can sense them.
No when there is wind the particles move in the same chaotic way but on top of that there is a net movement in a particular direction and that will be called wind.
When I think in my head I imagine the vehicle still moving and the road is what is stationary so I do not modify the frame of reference.
That is right, but the wind speed in all the circumstances that we have been discussing is a tiny fraction of the average individual speeds of the air molecules.
That is fine when considering the interaction between the wheels and the stationary platform, but when considering the interaction between the other wheels and the treadmill, the stationary frame of reference is not the best choice.
However you can still do it, as long as you remember to include the work done by the treadmill on the vehicle, as well as the work done by the vehicle on the treadmill. What you seem to keep doing is forgetting the work done by the treadmill, and then concluding that conservation of energy prevents the vehicle from moving to the right.
Going back to my aircraft thought experiment. The aircraft is travelling at 200 m/s, I get out my seat and walk forwards at 1 m/s, I weigh 70 kg. How much energy did I have to expend to accelerate from 200 m/s to 201 m/s in the frame of reference of the ground? From the ground frame of reference my kinetic energy has increased from 1,400,000 joules to 1,414,035 joules. A difference of 14,035 joules.
Any experiment where my diagram is respected will show that vehicle can not move from left to right. There is not even one experiment showing that.
What do you mean by aircraft ? For me an aircraft will be something that travels in air not on ground so something like an airplane.
I can not imagine you getting out of an aircraft and then walking.
But say you are referring to an airplane driving very close to ground and then you get out of that (it will be very painful) as that 200m/s speed of aircraft is relative to stationary ground so if you get out of the airplane as soon as you touch the ground all you kinetic energy will be reduced close to zero in seconds so you will likely not survive let alone be able to walk.
Have you ever got down from a moving vehicle like maybe a train ? It will need to move very slowly so that you are able to absorb all that change in kinetic energy else you will get hurt.
There are at least two, and you've posted one yourself. I doubt if there will be another because it's obvious you will find some issue that allegedly negates the experiment.
How about you show the experiment that proves your hypothesis?
My apologies, but I thought it was obvious. I am a passenger in a normal aeroplane flying at normal cruising altitude at 200 m/s. I stand up from my seat and walk down the aisle of the aeroplane towards the front of the aeroplane at 1 m/s, relative to the aeroplane. I weigh 70 kg.
To an observer on the ground (using the ground frame of reference), by getting up and walking along the aisle, I have accelerated from 200 m/s to 201 m/s. To this observer on the ground, I have increased my kinetic energy by 14,035 joules. Where did this energy come from?
That is because you do not understand the difference between my diagram and a flipped vehicle.
even if I show it is now working you will think I did something to trick you
My apologies, but I thought it was obvious. I am a passenger in a normal aeroplane flying at normal cruising altitude at 200 m/s. I stand up from my seat and walk down the aisle of the aeroplane towards the front of the aeroplane at 1 m/s, relative to the aeroplane. I weigh 70 kg.
To an observer on the ground (using the ground frame of reference), by getting up and walking along the aisle, I have accelerated from 200 m/s to 201 m/s. To this observer on the ground, I have increased my kinetic energy by 14,035 joules. Where did this energy come from?
I did not understand because your proposal demonstrates nothing.
You are not between two mediums you are just on one medium that moves relative to the ground. So you walking inside the plane requires energy that you will provide by burning some extra calories while in motion at 1m/s and as soon as you stop walking you will be back at 200m/s.
I am not talking about operating between two mediums. I'm taking a step back and considering a simpler case, which will turn out to be very relevant to the original more complex case.
I ask you again, to the observer on the ground (in my thought experiment above), I have increased my kinetic energy by 14,035 joules. Where did this energy come from?
I may not have been very clear. In your tough experiment there are two sources of energy both contributing to your increase in kinetic energy.
Out of that 14035J you contributed 35J and the plane contributed with 14000J. You used some of your stored energy from food while plane used kerosene or whatever that plane was using for fuel.
This will not apply to vehicle having a single energy source (wind energy).
That is correct. So relative to the ground, I have accelerated to a speed slightly in excess of that of of the aeroplane, and I was able to do that by taking the majority of the required energy from the aeroplane. You have repeatedly claimed that it is impossible to take energy from a moving medium when moving faster than that medium, whether that medium is a treadmill, a sliding piece of paper, the air, or the floor of the aisle of an aeroplane. In your calculation above you have just demonstrated that this is indeed possible.
Yes it does apply. It shows that the generator and motor of the vehicle only have to provide a portion of the kinetic energy required to increase the speed of the vehicle in excess of the speed of the moving medium. The remainder of the kinetic energy is provided directly by the moving medium. So while the motor will itself return a little less kinetic energy to the vehicle than was taken by the generator, the additional direct contribution of the medium will more than compensate for this. So the vehicle can accelerate beyond the speed of the moving medium.
In my example above my internal motor (my muscles) only had to supply 35 joules to gain 14,035 joules (relative to the ground). So if my muscles were powered by some small hypothetical wind turbine, held in my hand and in contact with the air outside of the aeroplane, that generator would only have had to extract 35 joules out of my 1,400,000 joules of kinetic energy (travelling at 200 m/s). So I would lose 35 joules of kinetic energy through the drag of the hypothetical generator, but gain about 14,035 joules of kinetic energy through the propulsion of my internal motor.
Excluding energy storage in the experiments is not easy - at least I sone see a very simple way. It is clear that there is no battery or spring storage - they are just not there and a bayttery would also need a motor. Kinetic energy (like flywheel) goes up when the vehicle gets faster, so it can not provide energy. It is only theoretical air pressure in the free space before / behind the fan. Without a container the energy/ pressure field would not stay there very long - more like lenghtscale divided by speed of sound - so in the low ms range. Compared to this the experiment with the free running vehicle on the tradmill was allready very long. A few seconds may not look long, but it is sufficiently long. Even the vehicle size divided by wind speed would be short compared.
Similar for the larger backbrid vehicle, with a pressure field that may last a few 1/100 of a second and time traveled at speed higher than the wind of more like a minute or more.
There is another point that shows that the vehicle did harmess the power of the wind, even if at the wind speed: When held at position at the treadmill there was a forward force, as when left free the vehicle accelerated forward. This forward force means the the wheels could use even more force and generate extra power. So the vehicle would be able to generate some power even if at the speed of the wind. The time the vehicle was hold in position pretty long and the time is definitely sufficient to esteblisch a steady state air pressure around the prop. There is also absolutely no reason to assume one could not hold the vehicle longer before letting it run forward. So this is steady state and thus has nothing to do with energy storage. It may be against some peoples intuition, but the experiment still shows it.
The though experiment with the man walking in the plane is good, as it shows that the use of just power / energy to avoid looking at forces can get pretty complicated when looking at different refrence frames. Similar complications also apply to the system on the treadmill: you get different energies / power when you use different refrence systems. So looking at the power is tricky and prone to error. It is much easier to look at force and speed seprate. The forces don't change when one changes the reference system, and the speeds simply add.
Assuming without checking or agreeing that your math is correct...
6Wh = 21600Ws
4800Ws = 1.5Wh.
and so on. Not keeping your units tidy can make things look different--and wrong.
and then you have to ask by what mechanism is the propeller compressing this air if the wind is pushing the vehicle and not the other way around?
The wind is pushing the vehicle and the blackbird takes a big part of that energy and put it back in the propeller generating an "artificial wind" in the opposite direction. When vehicle is way below half the wind speed the so called artificial wind will be stronger than the actual wind and this is where energy is stored as pressure differential.
This is Wind Cube territory, with apologies to real companies called Wind Cube.
The wind is pushing the vehicle and the blackbird takes a big part of that energy and put it back in the propeller generating an "artificial wind" in the opposite direction. When vehicle is way below half the wind speed the so called artificial wind will be stronger than the actual wind and this is where energy is stored as pressure differential.
How can there be an 'artificial wind' coexisting with and opposite to the actual wind? Can you demonstrate that somehow with a fan or something?
And setting that aside, if the resultant artificial wind is stronger than the real wind, where would the energy for that come from? Wouldn't that violate your conservation of energy principles?