Does the jello power the cart?
The idea of ground power that supports the above notion, is pre-Newtonian. All of the energy comes from the wind. That is what Newton says, and will be so for all velocities that the cart will encounter. The argument for "equivalent frames" is a sophism.
Sophism:
"Sophism can mean two very different things: In the modern definition, a sophism is a confusing or illogical argument used for deceiving someone. In Ancient Greece, the sophists were a group of teachers of philosophy and rhetoric."
Both abundant in this thread.
The gearing is not a source of power or energy, but a governing mechanism. In fact, it is simple positive-feedback controller. If the ratio is greater than one, an incremental increase in one, will cause a larger incremental increase of N:1 in the other.
So, prop drives cart (increased velocity) drives wheels (further increase) and so forth. Is is the rather like the 'opposite' of the governors found on early stationary steam engines.
If there is sufficient energy available, this simple positive-feedback will drive the propeller at an ever increasing rate, and that may increase the rate of acceleration, but the terminal velocity will be limited by the available power, and the forces of friction and drag that impede it, in the usual way.
Also, this gearing allows the cart to be driven by kinetic energy from the propeller's rotating mass. The energy stored in this mass can drive the cart, even if the blades of the propeller are incapable of providing any thrust. This is useful. When the opportunity arises, the gearing comes into play, driving the propeller ever faster by the wind but augmented by the stored energy, meaning that a higher average velocity may be achieved.
Straight forward engineering can be used to optimize this system, so claims for performance over and above this would require very careful measurement, and not the finger in the air measurements of the street.
The treadmill does nothing to support the cart in this respect, so there is no need to think too much about that gimmick.
That's all fascinating, humber. Your genius in mechanics is astounding. Please enlighten me further - how does the above analysis fit with your other insight, that if someone fell out of the cart travelling at windspeed, they'd get sucked into the propeller?
The calculations do not include any real or plausible figures for the system efficiency, or how that may vary with prevailing conditions. So?
Propellers have v/f curves. They are not simply a linear function of say, V, but complex profiles. The tangent of that profile can be regarded as the V/F or "gearing ratio" for any given rpm. However, the total power available, varies and is always less than 100%. If in the calculations the total energy budget is ignored or fitted, then there will be no surprise that a positive result is achieved. Also, sailing boats are not wind carts!!
If external gearing is added to effectively modify the propeller's 'normal' profile, you can perhaps mimic the behavior of a variable pitch propeller.
So, as I have said, the gearing tends to drive the system to maximum V for any level of available power. That may result in an overall gain in efficient extraction, but nothing more than could not be achieved by other means. So what?
ETA:
It is common to see this in power conversion. The author lays claim to a highly efficient converter, while avoiding the now discredited, and so unpopular, idea of over-energy. There may be 20 pages of detailed calculation, yet the authors seem to ignore the fundamental fact that( P = I^2*R) always applies no matter how fancy the "math". It is then a matter of looking for where the author has included some resistance to stop his equations 'exploding' to infinite current, but not included them elsewhere. The values are arbitrarily assigned, ( usually justified by some simple "assumption") and then inconsistently applied. When these sophims are removed, you get back to a standard device, as in the cart.
You like pretending others are using sophistry, don't you. It's called projection. Trust me, I'm a shrink.
The idea is that the belt is the wind. We have been through this. Every time that this is discussed, it always ends with some example where if I complete the course, I would end up in arithmetic agreement, because that is the inevitable outcome of the assumption that fosters that idea. That's not the the difference at all. In the cart treadmill, there are more differences than that. It is not even logically consistent.
The treadmill belt is said to be an "equivalent frame of reference", but I say that it is a model, and that the limitations of that model will certainly allow me to tell any 'wind' so generated, from the same wind in the real environment. It does not depend on visual clues, or such. They are definitely not the same. Not even close.
Odd. If I was so sure that I could tell the difference, and not by reference to outside clues, rather than just state that, I'd give an example, just to show that I'm not a complete sophist, y'know?
The idea of proving a wind driven device without using the wind is laughable.
Yeah, as laughable as testing an an aeroplane by holding it still and blowing air over it with a big fan! Crazy man.
You have faith I have reality.
So you're another who thinks there's something called 'real wind'. I wish one of you would define it.
Mender, you say that when standing on the treadmill moving at 10kph, you feel a 10khp wind? Yes, I agree.
But there is a big difference between that wind, and a real wind.
To feel the treadmill wind, I must travel with the belt. My shoes must provide a reactive force to the belt. If I don't move relative to the belt, then the forces of the 'wind' and shoes are equal but opposite. That is also the maximum force that I will ever feel. To move back against the belt, the friction of my shoes must fall, but that will also reduce the force of the 'wind' against me.
The magnitude of the forces either way is a directly proportional to the friction to the belt. No friction = No Force = No 'wind'. That's what the cart does. It is due to its design. Another type of cart , may not do this. London's device is different. It simply does not stay on the belt.
What if the friction of his device, had been 'just so' as in the cart. Would that mean that his device does work? Couldn't I modify it so it does pass this friction test?
This is not the case with real wind, my friction can be zero to the ground, and yet I can be blown with it.
You know, I am not playing Devil's Advocate here, Mender. If you see no problem with the above, we occupy two different worlds.
As I've said once already, humber, your problem is that your frame of reference is utterly fixed to the bit of ground you stand on. That is the limit of your imagination (assuming, again, that you're not quite clear on all this by now and just enjoy pretending with increasing sophistry that you see a different, better truth - personally, I think that's the most likely).
Let's try another little test. You're outside. There's no wind - no 'real wind' as you lovingly call it. Why is that? Well, it's because your feet and all the rest of you is moving at the same rate as the ground and all of that is moving at the same rate as the air. A condition of 'no real wind' is when
the wind is blowing Eastwards at the rate of the ground. But that's odd. Zero real wind is different speeds at the equator and the poles and all other latitudes in between. So please, do tell us what 'real wind' is.
I could extend the relativization of 'real wind' to positions in earth orbit round the sun, or the sun's motion round the galaxy, or the galaxy's progress through the universe, but maybe that would give you too big a headache.
Your insistence that Galilean relativity is wrong because one frame has 'real wind' and another doesn't - that (tsig) is what is laughable. Or perhaps you'd like to actually tell us how you would know the difference, what difference there would be, without reference to external cues. Or maybe you'd like to offer a definition - a full and frank definition - of 'real wind'. Until you do so, we can only assume it is something like "air that is moving over stationary ground". So go on, make it a full definition: where is there stationary ground? Is there a bit hovering where the Big Bang happened? Everything else seems to be going somewhere fast.
You won't, of course, answer these questions, because you can't. You will employ more sophistry as usual. We've had gears that are like limiters but in reverse, drive-shafts that are acting as torsion springs, slipping and sliding wheels, passengers falling into the prop, momentum of a tiny plastic propeller causing a cart to advance up the treadmill, and probably many I haven't even bothered to read. I would not be at all surprised to find your next 'fact' about the cart to be that the rotation of the wheels creates a small electrical charge, and it is static replusion which propells the vehicle forward.
