Down wind faster than the wind
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sol invictus
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"Conversation" over.
sol invictus
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That's a thought - write a short statement about the fact that the treadmill experiment proves the cart goes DDWFTTW. Get humber to agree that if Dela agrees with the statement, humber will admit he was completely wrong all along, will eat humber pie, and will stop polluting this forum with gibberish. Then (and only then) it might be worth sending it to Dela.
Meaning. I cannot name an object in motion w.r.t. the ground, that does not have KE. I cannot name a wind blown object that does not have KE above that same object at rest.
My treadmill contradicts "basic Newton mechanics"
sol invictus
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That's better.
For the first, any object in motion wrt the ground. For the second, any wind-blown object.
Tell me, humber - when you see the forumla KE = (1/2)mv2 written down in physics texts, do you notice any subscript on the "v", like vwrt ground? No?
Gee, I wonder why not?
Gee, I wonder what that lack of subscript may mean?
It means that without a subscript, the case is entirely general, so that means that I can add that subscript as I wish. So please do that, and give me an example of an object, vwrt ground, otherwise the treadmill is wrong.
I get to choose. That's what equivalence "means". If a break none of the rules of physics while doing so, I am at complete liberty to "chose that frame"
Yes indeedy, "all frames are equivalent". Being that the Earth is nearby and has massive gravity, and both my real world cart and the treadmill are fully engaged and immersed in the effects of that, I may as well use the ground as any other. It's more convenient.
It seems to me that you are making the same mistake as followers of Post Modernism. They deny an absolute "realty" ( all PM words are in double quotes) and so infer that all views of reality are the same. This is obviously not the case, unless you think that Newton's view is equal to that of those that preceded him. In this thread, "all views are equivalent" seems to mean that any view is equivalent, yet to think that is is stupid of me to use the ground, yet that objection denies your own claim, unless you think you have "a better one".
The problem is not of that, but in assuming that the treadmill is one of those "equivalent" views.
ETA:
As for KE. It is not relative in the same way as velocities are. To view the world in this way is primitive, and indeed anthropomorphic. Perhaps on another planet, where light is poor, its creatures would have perhaps evolved senses to "see" acceleration, or momentum.
Viewing the treadmill, they may exclaim "WTF! Where's the momentum gone?"
Put as gyroscope in the real windcart. Model that on the treadmill. What happens? Does it stop?
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Humber,
Given that you still hold such strong views opposing the validity of the treadmill videos (even if those videos are taken to be "genuine", by which I simply mean not deliberately faked in some way or other), and also given the extraordinary length of this thread, I'm wondering if you could attempt to summarise your position at this time. I'd suggest your summary could cover two main aspects of your thinking.
Firstly, an outline of the kind of physics you believe to be appropriate and reasonable in discussions about the claims of a cart going DDFTTW. You seem to indicate (in some places at least) that you see Newtonian physics as okay, but you also seem vehemently opposed to using inertial reference frames. Maybe I've misunderstood your position, and I certainly don't claim to be any kind of "expert" on these matters, but from my perspective at least it would be good if you can clarify where you stand so people at least know what "laws" or "principles" you are using. Just to take one fundamental example, how do you believe the "velocity" of some object needs to be measured? Can you give some examples perhaps, say one for an object moving on the surface of the earth, and another for an object is some distant part of space? As far as I can see, you seem to believe there is some kind of absolute frame of reference and only that is valid when doing various calculations and so on. How do you calculate kinetic energy? Does it depend on anything other than mass and velocity of the object?
With respect to inertial reference frames, can you give a simple worked example where using different reference frames clearly fails to produce consistent or correct results? (I'm talking about an example with actual values and calculations so everybody can follow through the details.)
Secondly, I think it would be useful to get a clear summary of the specific issues that you see as being problems when it comes to what is shown in the various videos and in the related arguments supporting them. It seems pretty clear you don't agree that using different (inertial) reference frames is a valid approach. Is this specific to the treadmill in some way, or any such frame? There has been talk of other things also, but trying to go back through more than 2600 posts (not all yours obviously, but a lot are from you!) and figure out where you stand now on all the various details that have come up at one stage or another is very difficult because of the number of posts and also the long time period over which this thread has been active. Perhaps you have altered your position on some things that were talked about a long time back? I really don't know. Hence a complete, but clear and concise summary of your current position in this respect also might help to refocus the debate.
Hopefully you see what I'm trying to get at. Do you think you could do this? I really think it would help all of us.
Hmm. I see some other recent posts published while I've drafted this are asking for similar things. But I'll leave this to add to the chorus...
Given that you still hold such strong views opposing the validity of the treadmill videos (even if those videos are taken to be "genuine", by which I simply mean not deliberately faked in some way or other), and also given the extraordinary length of this thread, I'm wondering if you could attempt to summarise your position at this time. I'd suggest your summary could cover two main aspects of your thinking.
Firstly, an outline of the kind of physics you believe to be appropriate and reasonable in discussions about the claims of a cart going DDFTTW. You seem to indicate (in some places at least) that you see Newtonian physics as okay, but you also seem vehemently opposed to using inertial reference frames. Maybe I've misunderstood your position, and I certainly don't claim to be any kind of "expert" on these matters, but from my perspective at least it would be good if you can clarify where you stand so people at least know what "laws" or "principles" you are using. Just to take one fundamental example, how do you believe the "velocity" of some object needs to be measured? Can you give some examples perhaps, say one for an object moving on the surface of the earth, and another for an object is some distant part of space? As far as I can see, you seem to believe there is some kind of absolute frame of reference and only that is valid when doing various calculations and so on. How do you calculate kinetic energy? Does it depend on anything other than mass and velocity of the object?
With respect to inertial reference frames, can you give a simple worked example where using different reference frames clearly fails to produce consistent or correct results? (I'm talking about an example with actual values and calculations so everybody can follow through the details.)
Secondly, I think it would be useful to get a clear summary of the specific issues that you see as being problems when it comes to what is shown in the various videos and in the related arguments supporting them. It seems pretty clear you don't agree that using different (inertial) reference frames is a valid approach. Is this specific to the treadmill in some way, or any such frame? There has been talk of other things also, but trying to go back through more than 2600 posts (not all yours obviously, but a lot are from you!) and figure out where you stand now on all the various details that have come up at one stage or another is very difficult because of the number of posts and also the long time period over which this thread has been active. Perhaps you have altered your position on some things that were talked about a long time back? I really don't know. Hence a complete, but clear and concise summary of your current position in this respect also might help to refocus the debate.
Hopefully you see what I'm trying to get at. Do you think you could do this? I really think it would help all of us.
Hmm. I see some other recent posts published while I've drafted this are asking for similar things. But I'll leave this to add to the chorus...
So 1:
We are allowed to choose any frame.
2: Humber are choosing the ground as the frame.
3. Humbers conclusion seems to be that his choice of frame is the only correct one completely ignoring what he wrote 2 seconds ago.
Humber I see a problem with humberian physics. You like the earth as the reference frame. No problem with that. You clearly get KE=0 for the cart in the treadmill if it is at the same place.
I like the belt as my reference. I clearly get a nonzero KE for the cart.
This is of course no problem for newtonian mechanics but seems to be a huge problems for humberian mechanics. Is this solved yet in humberian mechanics? My guess of a solution is that. The humber frame is always the correct frame and no other frame can be correct. This is of course in disagreement with #1 above but this can of course be ignored.
The humber frame is the frame that humber likes the most.
We are allowed to choose any frame.
2: Humber are choosing the ground as the frame.
3. Humbers conclusion seems to be that his choice of frame is the only correct one completely ignoring what he wrote 2 seconds ago.
Humber I see a problem with humberian physics. You like the earth as the reference frame. No problem with that. You clearly get KE=0 for the cart in the treadmill if it is at the same place.
I like the belt as my reference. I clearly get a nonzero KE for the cart.
This is of course no problem for newtonian mechanics but seems to be a huge problems for humberian mechanics. Is this solved yet in humberian mechanics? My guess of a solution is that. The humber frame is always the correct frame and no other frame can be correct. This is of course in disagreement with #1 above but this can of course be ignored.
The humber frame is the frame that humber likes the most.
John Freestone
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An answer would do for starters. I may have missed some and I apologise if I'm asking you to repeat, but this is my honest state of understanding of your views:
Bullets travelling at the same speed as a person can kill that person. You have not given me anything to suggest you believe otherwise, but in this case it is such an odd belief that I asked for confirmation of it. The fact that spork believed otherwise seemed to surprise you, when tsig cleverly wheedled the admission out of him.
If one falls out of a vehicle with a prop on the back, travelling at windspeed, he will get sucked into the prop. Again, most kids can deny this by the time they arrive at high school, so I asked for confirmation - do you stand by that statement?
Tell me what the kinetic energy is of an object sitting on the ice at the North Pole, and that of the same object sitting on the equator. Perhaps explain how they differ, if they do, yet have no velocity w.r.t. the ground under them, or explain how they have the same k.e. when one is moving a thousand miles an hour faster than the other. Any answer will do. None has been provided.
It is absolutely obvious that I have been trying to explain my understanding of physics to you as clearly as possible and asking you to explain yours to me. It is absolutely obvious that I cannot understand those points above, and am not asking for more answers because I'm just never satisfied.
Your replies are to say you've read my blog, my views are those of a sophomore reading too much Kafka or that it's like I've discovered porn and don't know why I enjoy it. "Trivial and juvenile responses"? - you're projecting again.
No, you are doing exactly as I claimed. Your are first drawing the wrong conclusion from equivalance, and then actually denying my perspective, then claiming your "belt view" as the same, while not realising that they must be the same. Any differences indicate that one of us is wrong. My view is the reality of the ground, and that in which the real cart works. That means that any differences between that reality ( or any other) must be your error.
Firstly the treadmill is not a frame of reference. That's flatly wrong.
When you are in a car in the real world and looking out of the window ( or other means) that is a "frame of reference". A video screen, a PC, and some pedals makes a "driving simulator" but not a frame of reference. Putting that on a belt makes it a "driving simulator traveling on a belt"
And so you may.
Err..No. The belt is a very limited expression of what could be though of a "frame of reference", though that's usually called a model. It is in fact so limited ( a model) that it leads you to the wrong conclusion.
And you yours.
The difference is that humberian physics only "work" in the humber frame but standard physics works in all frames if you know what you are doing.
This but the KE is zero in one inertial frame but 10 in another intertial frame don't matter in standard physics.
So I get the same result if I use the humber frame or any other inertial frame.
Marcus
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No weight is needed. Simple photographic means could show if the wheels are slipping or not.
I don't get this slipping/non slipping. It is not only that I still don't know if the wheels go faster or slower compared to the non slipping case.
I also don't see the relevance at all. There are no problem if someone manage to have a slipping cart going faster than the wind. There are no reason to say, ok, the cart works but you are cheating because it is slipping or the weight are to low or something similar.
I also don't see the relevance at all. There are no problem if someone manage to have a slipping cart going faster than the wind. There are no reason to say, ok, the cart works but you are cheating because it is slipping or the weight are to low or something similar.
Surely you have my stance by now? The faking has been excluded in my claim. It is simply not necessary,because by and large, there is little to explain. In #7 (?), the objection of an external wind source is addressed. Well maybe, but if I were of a mind to think that you were cheating, then I would say that the fan was turned off for the toilet paper test. Pointless, because it proves nothing. So, yes I see them as "genuine". Yet, is does show at least two further flaws in the treadmill...
Really, this is silly. I make no extraordinary claims. Any of the measurement systems known to man can measure velocity. Again, the "frame of reference" idea has been tortured into submission. It really is not important.
There is nor need for "expertise" in this matter. It is not even a difficult subtraction. The idea is readily amenable to "though experiments", perhaps too easily. Why velocity, always velocity? Because that is the only one of nature's features that gives the desired effect of a new "frame". Apart from that, when you measure the mass ( or weight) of something do you then add the mass of the Earth to that? Ask your friends to literally help you "move house". You can add all the effects together, but if you want the difference, the useful information, then you must subtract it again.
Due to the earth;s rotation, the roof of a stationary car moves faster than the floor pan. So, there must be strain in the structure as a result. Do you include that?
No, I do not think that. When two bodies, two real entities, are described only by 'm' and 'v', then you have a simplified model those objects.
Take then into free space. and then collide them, while only observing the point of impact, then what would you expect other than "you can't tell".
So, first strip out all the information, so that you can then say "see, you can't tell". Science is said to expand out knowledge, not shrink it.
Utterly pointless, because it can't be actually applied in the real world
This is not my doing. There is no humberian physics'. I let is go, because the ideas it is so asinine, that it may as well be accepted as denied. I mentioned that Newton was a strange man, and hated Leibniz. I did this to say the "Newton the man", is irrelevant to his ideas. They have stood the test of time. Extended by Einstein, but still good enough for all but the most extreme conditions. This remark is seems makes me a "Leibizian". Quite bizarre thinking.
No, that is the point. No correct calculation can ever do that. If follows that any claims of a frame "gaining" a force or source of energy over another must be false. Two-object collision are only symmetrical under very limited circumstances. You say perhaps that can be so in the prop-wind is the same as wind-prop. No, they are not the same, because the circumstances change in each case. Also, instead of a golf ball hitting a bowling ball, how about a bowling ball hitting a glass window? Do you think you can calculate the glass-hitting-ball before the fact?
Makes you wonder doesn't it? Why? Sometimes that answer lies more in 'why' than the 'how'. Not really changed my mind. Naturally as I have thought about the details, and seen more videos (that's all the evidence I have), then I revise, but there is nothing of significance.
If you do go a long way back (first post from me I think). I mentioned the idea that the blades may be acting like the cart were tacking the wind. This was really not well thought out. I realised my error, and retracted the idea.
The real thrust of my argument is that the treadmill is NOT a frame of reference, so the cart staying on the belt is a problem of simple mechanics.
The details are perhaps interesting, but not relevant to the fact that is doing exactly what you see. It moves just a little faster than than the same cart motionless on the ground. Same level of KE.
No offense to you, Clive, but this idea of calculation has bee used rather like a magician forces a condition, so as to pull off the remainder of the process.
The idea or recreating frame of reference is impossible. The treadmill is not a time machine. If you do make a new and complete frame, it becomes a copy. Big engineering project. You may make a model as in the case of a wind tunnel, but actual velocity can never be simulated without motion. The closest is perhaps circular motion. Rather like Platt suggested.
Name one other simulator that does that? Aircraft are simulated, but the actual simulation is acceleration, with a very restricted, reciprocated displacement. No actual continuous travel. THAT IS NOT POSSIBLE unless it does travel. Also the observer is wrong in several ways. The only position that allows me to observe a stationary cart is when traveling along side it at windspeed. Right? OK that fits. The air around the treadmill is still, the cart is still so I can be still. How come I feel nothing when the treadmill is turned off?
Really? Then your maths is wrong, because it should. V = 0, so KE = 0?
The first translation is a vector, right? When KE =1/2MV^2, where is your vector?
You didn't put a scalar zero in there did you?
Last time Fredriks. If you mention the slipping again, you are on "fast scroll". I do not have to supply your understanding. Try thinking for yourself.
Friction and force transmission are related. How much do friction do you need if the force is tiny?
What if the friction is intermittent? When you brake while driving, the tire may squeal because the rubber is oscillating in reaction to slip-stick friction. Still stops you though, over time.
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sol invictus
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humber said:
Exactly! You finally got the point! You've repudiated all that nonsense you've been saying!
And..... back down into the gooey humberian morass of incomprehension we slip. All within the span of one post...
Oh well.
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Consider the original video. US frame rate 30fps. Aliasing above 15fps. Prop is symmetrical so that falls to 7.5fps. Video cameras uses sequential compression, keeping only the occasional full reference frame. Not so simple, and not done anyway. No attempt was made to demonstrate that the cart does not go backwards, a requirement that would need to be met for any claim to it being a frame, let alone a good model.
The wheels slipping is not the point. They can spin 100% of the belt speed, yet still not transmit significant force.