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This guy thinks 1.09g for Model S is suspicious because, um, physics
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Canuck
Well-Known Member
Hmmm... I thought...
Niels Bohr, a Danish Physicist who made significant contributions to understanding atomic structure and quantum theory once said: “if quantum mechanics hasn’t profoundly shocked you, you haven’t understood it yet.” Quantum physics has left scientists all over the world baffled, especially with the discovery that our physical material reality, isn’t really physical at all. “Everything we call real is made of things that cannot be regarded as real.”
Perhaps we're dealing with semantics in that we obviously must use our "reality" to discovery things are not regarded as real? But doesn't that beg the question as to what is real and isn't that way scientists are shocked? Another thing I've read about quantum physics is...
An independent reality, in the ordinary physical sense, can neither be ascribed to the phenomena nor to the agencies of observation. [3]
Then there's the problem of "reality" being changed just by observing it...
One of the most bizarre premises of quantum theory, which has long fascinated philosophers and physicists alike, states that by the very act of watching, the observer affects the observed reality.
Anyways, interesting stuff. I'm not sure you can put REALITY in all caps to describe how quantum physics determines what is real. I think it might be better to put it all in small letters, then turn it upside down, and that best describes it. All we have is our reality so I don't know any other way we could test theories of conduct experiments so I do get your point. And I am certain you have more experience than me in this stuff.
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deonb
Active Member
Haven't we learned by now to not blame reality when our observations don't match our preconceived notions anymore?
See Galileo Galilei.
I personally have no problem with a reality that includes quantum mechanical effects.
This is called quantum woo. In other words, complete bullshit.
Things at very small scales escape our intuitive understanding, but yet those things still power our macroscopic world. If you know what to look for, very demonstrably. It's not this mystical bullshit. Our perception is simply at the scale at which our brains evolved, and we still make accurate predictions at this scale. Quantum physics will never invalidate F=ma, sorry.
Canuck
Well-Known Member
Say it like it is! Ha.
I'm not so inclined to readily discount this debate as you are, especially since the debate on this issue between Einstein and Bohr has been called:
...one of the highest points of scientific research in the first half of the twentieth century because it called attention to an element of quantum theory,quantum non-locality, which is absolutely central to our modern understanding of the physical world. The consensus view of professional physicists has been that Bohr proved victorious in his defense of quantum theory, and definitively established the fundamental probabilistic character of quantum measurement.
But you can call it all BS if you want. It took Einstein a lot more words to lose the debate so no need to waste your breath...
Say it like it is! Ha.
I'm not so inclined to readily discount this debate as you are, especially since the debate on this issue between Einstein and Bohr has been called:
...one of the highest points of scientific research in the first half of the twentieth century because it called attention to an element of quantum theory,quantum non-locality, which is absolutely central to our modern understanding of the physical world. The consensus view of professional physicists has been that Bohr proved victorious in his defense of quantum theory, and definitively established the fundamental probabilistic character of quantum measurement.
But you can call it all BS if you want. It took Einstein a lot more words to lose the debate so no need to waste your breath...
You're simply misunderstanding what they are saying. I guess I need to repeat it, the world consistently works in a strange and unintuitive way at very small scales, but that behavior in itself builds the world we know and understand very well. If you take anything from what you posted and apply it the macroscopic world, you're JUST PLAIN WRONG. Woo, for shorthand.
mikeash
Active Member
Looks like a typical "spherical cow" analysis of the situation. Physicists love that sort of thing. The better ones realize that it's an approximation only, and that you need to refine the model to better approach reality. Bad ones like this author assume that their spherical cow model is reality, and difference with measurements means the measurements are wrong.
He says that coefficients of friction are "generally a number less than one" and gives as proof a site that not only lists many coefficients greater than 1, but whose one relevant entry refers to the combination of "tire, dry" and "road, dry." Zero acknowledgment of the fact that there are different types of road surfaces, different types of tire material, and different ways to build tires, all of which will greatly influence the coefficient of friction. In fact, I would say that this site actually gives considerably support to the 1.1g claim: if 1 is a sufficiently standard coefficient of friction to be listed as a generic "tire + road" number, then surely it's not a big deal to come up with variations of tire and road which vary by 10% from that number.
There's nothing magical about that 1.0 number for coefficient of friction. There's neither a theoretical nor practical barrier at that point.
This article, if you remove the incredulous tone, would make for a good discussion in an undergrad physics course. But it's a ridiculous article to find in Forbes. I guess they'll just publish any random thing.
He says that coefficients of friction are "generally a number less than one" and gives as proof a site that not only lists many coefficients greater than 1, but whose one relevant entry refers to the combination of "tire, dry" and "road, dry." Zero acknowledgment of the fact that there are different types of road surfaces, different types of tire material, and different ways to build tires, all of which will greatly influence the coefficient of friction. In fact, I would say that this site actually gives considerably support to the 1.1g claim: if 1 is a sufficiently standard coefficient of friction to be listed as a generic "tire + road" number, then surely it's not a big deal to come up with variations of tire and road which vary by 10% from that number.
There's nothing magical about that 1.0 number for coefficient of friction. There's neither a theoretical nor practical barrier at that point.
This article, if you remove the incredulous tone, would make for a good discussion in an undergrad physics course. But it's a ridiculous article to find in Forbes. I guess they'll just publish any random thing.
Canuck
Well-Known Member
Really? I don't even understand what they are saying. I framed the issues with quotes directly from Neil Bohr and I referenced debates he had with Einstein on this issue, but I don't even understand what they are saying? I can see you saying it's all BS, that everything can be measured and quantified, and even though the world may work in strange and unintuitive ways at very small scales, that behavior in itself builds the world we know and understand very well. There's no mystery to it, we can account for it, measure it, predict it, etc. That's fine.
But to say I don't even understand what they are saying? Ouch. I thought I was just framing the debate. I wasn't coming down on one side or the other but simply framing the issue. But now I find out I have no idea what I'm talking about and I'm:
All in CAPS too - which means I'm obviously wrong. I'm mean, it's in CAPS.
Thanks for the debate. We'll agree to disagree. I think I understand what they are saying. Not all the intricacies of course, but I think I get the main points.
Hi Canuck,
You said:
My guess is there will be people on this forum, perhaps AWDtsla included, who've studied physics to at least bachelor's degree level. I have. I don't know of any physicists, including some people I know vaguely at CERN, who would agree that a theory can be correct if it doesn't match observable effects. Validating hypotheses against observable effects remains the cornerstone of physics today. In physics, all theories are continually on trial, and are abandoned if they can't account for observable phenomena. The original meaning of the word 'proof' was 'to test'.
What's the means of proving a theory correct it it doesn't match observations or accurately predict something? It can be self-consistent, but that makes it maths, not physics.
I think AWDtsla is saying is that quantum physics:
1) is non-intuitive to our primate brains
2) but *is* comprehensive by humans and very amenable to making predictions that can and have been verified experimentally
3) produces effects at the macro scale that match our intiutive understanding
It's worth remembering that our ability to understand quantum physics and use it to make predictions is why we can build micro-electronics, and from there things such as the car we're all somewhat obsessed by. We spend billions smashing very small things together at high energy to test the standard model. So far, it's holding up well.
Perhaps you're reading about hypotheses outside the standard model, which are interesting but generally have problems and are definitely in the 'maybe' pile for the majority of the physics community. It's also true that human perception is fallible, and to a certain extent, things such as 'past', 'present' and 'future' and hence 'cause and effect' are artefacts of how our brains work more than how the universe is constructed. It would help if you cited some of what you're referring to.
On a final point, good physicists try not to close down debate on interesting ideas just because they aren't complete yet. Proposing things outside of mainstream thinking is one of the ways we progress. Most of those ideas don't survive scrutiny, but every now and then, they change our understanding fundamentally.
You said:
My guess is there will be people on this forum, perhaps AWDtsla included, who've studied physics to at least bachelor's degree level. I have. I don't know of any physicists, including some people I know vaguely at CERN, who would agree that a theory can be correct if it doesn't match observable effects. Validating hypotheses against observable effects remains the cornerstone of physics today. In physics, all theories are continually on trial, and are abandoned if they can't account for observable phenomena. The original meaning of the word 'proof' was 'to test'.
What's the means of proving a theory correct it it doesn't match observations or accurately predict something? It can be self-consistent, but that makes it maths, not physics.
I think AWDtsla is saying is that quantum physics:
1) is non-intuitive to our primate brains
2) but *is* comprehensive by humans and very amenable to making predictions that can and have been verified experimentally
3) produces effects at the macro scale that match our intiutive understanding
It's worth remembering that our ability to understand quantum physics and use it to make predictions is why we can build micro-electronics, and from there things such as the car we're all somewhat obsessed by. We spend billions smashing very small things together at high energy to test the standard model. So far, it's holding up well.
Perhaps you're reading about hypotheses outside the standard model, which are interesting but generally have problems and are definitely in the 'maybe' pile for the majority of the physics community. It's also true that human perception is fallible, and to a certain extent, things such as 'past', 'present' and 'future' and hence 'cause and effect' are artefacts of how our brains work more than how the universe is constructed. It would help if you cited some of what you're referring to.
On a final point, good physicists try not to close down debate on interesting ideas just because they aren't complete yet. Proposing things outside of mainstream thinking is one of the ways we progress. Most of those ideas don't survive scrutiny, but every now and then, they change our understanding fundamentally.
deonb
Active Member
It's not like the world works intuitively at large scales.
a) Take a star. Any star.
b) Have planet A move away from it at 0.6 C (60% of the speed of light)
c) Have planet B move away from it at 0.6 C in the opposite direction of A
Now go stand on planet A and measure planet B's speed.
It's not 1.2 C.
OK, I'll weigh in on this. I have a couple of engineering degrees from accredited schools (see signature), I call BS immediately when I see the claim in the article "And that’s why I’m skeptical of the claim that the Tesla Model S, or any other car, accelerates faster than gravity."
The author is saying that no car can accelerate "faster than gravity" - which to me, means 32 feet per second per second.
Check out the acceleration of any funny car or top fuel dragster, and it is clear that all kinds of cars can "accelerate faster then gravity," unrelated to the Tesla. You can show this any day of the week by mounting an accelerometer on a car (including a Tesla) - this will tell you exactly what the acceleration is, and any current performance Tesla exceeds 32 f/sec-sec.
The author is saying that no car can accelerate "faster than gravity" - which to me, means 32 feet per second per second.
Check out the acceleration of any funny car or top fuel dragster, and it is clear that all kinds of cars can "accelerate faster then gravity," unrelated to the Tesla. You can show this any day of the week by mounting an accelerometer on a car (including a Tesla) - this will tell you exactly what the acceleration is, and any current performance Tesla exceeds 32 f/sec-sec.
I second this. The scientific method is to observe, postulate a hypothesis, design experiments, and then discern if your hypothesis was invalidated by experimental results.
Instead -- the professor postulated a hypothesis (physics model) that was already invalidated by experimental results.
But, instead of making sure his hypothetical model wasn't too simplistic, he chose to disbelieve the experimental results. That's not science. That's daffy.
The article is online because everyone, including Fortune, is chasing clicks. Salacious or controversial headlines draw readers. I see this every day in the "News" section of Yahoo quotes. You can't believe the amount of nonsense and clickbait titles that appear in what one would expect would be a "news feed".
theslimshadyist
Active Member
sillydriver
Member
QM is not as mystical as was once thought. Hugh Everett realized its relation to objective, fully mind-independent reality over fifty years ago, with some physical loose ends tied up by Dieter Zeh (decoherence theory solving the preferred basis problem) in the 1970s, and various philosophical issues cleaned up by David Wallace and Max Tegmark more recently.
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physicsfita
Member
Ok, time for me to weigh in on this, I guess. Just to get the "credentials" thing out of the way, I have a Ph.D. in Physics and have been teaching at the university level for over 20 years (almost 30 if you include my time as a teaching assistant in grad school).
Now to the heart of the matter: The author of the Forbes article made (at least) two oversimplifications in his analysis -- the biggest one is that he neglects that the static friction of tires can get really weird to model. While it is a good rule of thumb that for most pairs of materials, the coefficient of static friction is less than 1, tires work very differently from the typical situation, and coefficients of static friction can easily exceed 1.
For the second thing, perhaps to simplify the presentation for his intended audience, he glosses over the fact that the maximum value of static friction is determined by the normal force exerted by the road surface up onto the car. This leads to him neglecting the effects of downforce (technically, a lifting force that's pointed downward). The normal force of the car could be greater that the force of gravity as a result. I tried to search for downforce data for the Model S, but couldn't find any. It could, even, be possible that the car body could even be producing some upward lift, which would make the normal force less than gravity. In any event, before the author attempts to make an assertion like his, he needs to get a handle on the size (and direction!) of that effect.
The biggest error he made, of course, is forgetting that Physics is an experimental science. Other cars are also out there with accelerations reported in excess of 1 g, which should give him pause to reexamine his assumptions.
Now to the heart of the matter: The author of the Forbes article made (at least) two oversimplifications in his analysis -- the biggest one is that he neglects that the static friction of tires can get really weird to model. While it is a good rule of thumb that for most pairs of materials, the coefficient of static friction is less than 1, tires work very differently from the typical situation, and coefficients of static friction can easily exceed 1.
For the second thing, perhaps to simplify the presentation for his intended audience, he glosses over the fact that the maximum value of static friction is determined by the normal force exerted by the road surface up onto the car. This leads to him neglecting the effects of downforce (technically, a lifting force that's pointed downward). The normal force of the car could be greater that the force of gravity as a result. I tried to search for downforce data for the Model S, but couldn't find any. It could, even, be possible that the car body could even be producing some upward lift, which would make the normal force less than gravity. In any event, before the author attempts to make an assertion like his, he needs to get a handle on the size (and direction!) of that effect.
The biggest error he made, of course, is forgetting that Physics is an experimental science. Other cars are also out there with accelerations reported in excess of 1 g, which should give him pause to reexamine his assumptions.
Correction: YOU understand quantum mechanics. I'm still shaking my head thinking WTH??
dgpcolorado
high altitude member
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