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Force multiplier
pcprogrammer:
--- Quote from: electrodacus on February 02, 2023, 08:42:33 pm ---You are likely thinking at electroboom vs Steve Mould and the chain fountain.
--- End quote ---
Nope the thread I had in mind was indeed the electroboom versus veritasium about the flow of electrons.
https://www.eevblog.com/forum/chat/electroboom-how-right-is-veritasium!-dont-electrons-push-each-other/msg4310218/#msg4310218
This is where you went on and on about whatever, purely for the trolling fun of it. So like Nominal Animal, I'm out of here.
electrodacus:
--- Quote from: pcprogrammer on February 03, 2023, 06:23:59 am ---
Nope the thread I had in mind was indeed the electroboom versus veritasium about the flow of electrons.
https://www.eevblog.com/forum/chat/electroboom-how-right-is-veritasium!-dont-electrons-push-each-other/msg4310218/#msg4310218
This is where you went on and on about whatever, purely for the trolling fun of it. So like Nominal Animal, I'm out of here.
--- End quote ---
Derek from Veritasium has less than basic understanding of physics and yes he is also wrong about the way energy is delivered from battery to load and it is through wires not outside the wires.
But I'm much more interested in debunking this simpler physics problem. If I can not explain this what are my chances in explaining how electrical energy is transferred from source to a load.
I think that the 3 examples illustrate best the problem. There can not be force multiplication in any of the 3 examples and all of them are equivalent. Example C should be best understood by people here and if anyone thinks that DC-DC boost converter can work with a floating ground is free to demonstrate.
Or if anyone things the 3 examples are not equivalent then again feel free to point the difference.
All of them have an input connection and an output and nothing else thus they can not work the way people may think they should work.
Adding a connection to ground from body / cylinder / GND will fix the problem and they will work as anyone will expect them to work as force multipliers A and B and step up DC-DC converter C.
cbutlera:
--- Quote from: electrodacus on February 02, 2023, 08:42:33 pm ---...
While I was trying to explain that no vehicle powered only by wind can exceed wind speed directly downwind without energy storage (in that particular case pressure differential is what allows exceeding wind speed for a limited amount of time), I got to narrow down what people fail to understand and it is now narrowed down to this Newtown 3'rd law and thus this examples trying to explain that no force multiplication is possible with a floating body.
--- End quote ---
"A book lies at rest on a table. The table is at rest on the surface of the Earth. By
Newton’s Third Law, the reaction force to the weight of the book is:"
* the gravitational force of the Earth on the book.
* the normal force exerted by the table on the book.
* the gravitational force of the table on the book.
* the normal force exerted by the Earth on the table.
* the gravitational force of the book on the Earth.As you are obviously interested in the teaching of physics and in particular correcting common misunderstandings of Newton's third law, I thought that this paper from Teaching Science: the Journal of the Australian Science Teachers Association would be of interest to you. The question posed above, and the abstract below both come from this paper, the emphasis is my own. I think it sheds considerable light on the misunderstandings that have been displayed in this thread, and in a number of earlier threads on the same subject.
ABSTRACT
"On entry to university, high achieving physics students from all across Australia struggle to identify Newton’s Third Law force pairs. In particular, less than one in ten can correctly identify the Newton’s Third Law reaction pair to the weight of (gravitational force acting on) an object. Most students incorrectly identify the normal force on the object as the Third Law force-pair to weight, rather than the gravitational force of the object on the Earth. This misconception may be constructed by students during instruction on Newton’s Second Law, and hence forms a logical, connected part of their knowledge structures, making it highly resistant to both traditional and more interactive instruction. The use of operational definitions of weight may contribute to this problem. We have addressed this issue by using a consistent and explicit definition of weight, and having students work through a short hands-on group activity using a bathroom scale and drawing free body diagrams. As a result, the majority of students, post instruction, can correctly answer this question (and similar ones); and they retain this learning beyond the end of semester. This teaching strategy and activity could easily be used in high schools, so that students develop consistent knowledge frameworks when first introduced to Newton’s laws."
Also of interest I think is this blog Making sense of Newton’s Laws. Written by science teacher Dr. Helen Skelton, describing her own journey from misunderstanding to enlightenment. I particularly like Dr. Skelton's opening sentence.
"You know those moments when something suddenly makes sense, but you’d never known it didn’t until you got it?"
For anyone who is unsure, the answer to the question above is E. See Dr. Skelton's blog for an explanation.
electrodacus:
--- Quote from: cbutlera on February 06, 2023, 10:40:05 am ---
As you are obviously interested in the teaching of physics and in particular correcting common misunderstandings of Newton's third law, I thought that this paper from Teaching Science: the Journal of the Australian Science Teachers Association would be of interest to you.
Also of interest I think is this blog Making sense of Newton’s Laws. Written by science teacher Dr. Helen Skelton, describing her own journey from misunderstanding to enlightenment. I particularly like Dr. Skelton's opening sentence.
"You know those moments when something suddenly makes sense, but you’d never known it didn’t until you got it?"
--- End quote ---
The book on the table example while good still has to do with gravity and I think that is not enough as people will maybe think Newtons 3'rd law only applies in those cases.
The other examples in the blog (second link) are much better but I feel any engineer or especially physics teacher will be offended if I were to provide that link.
I was thinking that you did not even needed to know Newton's 3'rd law to understand how those mechanisms in my drawing will react.
At first I was thinking people do not understand what air is and I concentrated on that and it took me quite some time to narrow down to Newton's 3'rd law.
People explaining those faster than wind vehicles as taking energy from the wheel to power the propeller not considering what taking energy from the wheel means (reducing vehicle kinetic energy).
I'm terrible at explaining things and I feel people only trust an experiment but even when I provided video of an experiment they blamed what they seen in the experiment on a bad setup to much friction or anything other that accepting that is the only way the experiment could work.
Why I'm almost the only one trying to correct this ? Especially after that video where the University Physics professor lost as it was unable to explain how vehicle works. I even seen some other University physics professors trying to invent fake math to explain how it works :)
The experiment is a big problem because it is incomplete and so wrong conclusions are drawn from that. Both the treadmill and the large model stopped the experiment before they got to peak speed. People just think that one it gets to peak speed it will stay at that speed but what will actually happen is that vehicle will start to slow down and will do so until is well below wind speed.
If they could see the full experiment they will realize that some sort of energy storage is involved even if they still do not understand air and that it is a compressible fluid.
cbutlera:
--- Quote from: electrodacus on February 06, 2023, 04:38:08 pm ---...
At first I was thinking people do not understand what air is and I concentrated on that and it took me quite some time to narrow down to Newton's 3'rd law.
...
--- End quote ---
So what is it that you think that people don’t understand about Newton’s third law? The paper describes the failure of many students to correctly identify Newton’s third law force pairs. Do you agree with this, or have you identified some other common misunderstanding?
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