Equation that predicts the increasing values of mass

In summary, the spinning top will become increasingly more massive as it speeds up towards a speed of c. The mass increase is only significant when the top is spinning at a speed of ~0.866c.
  • #1
8LPF16
191
0
Is there an equation that predicts the increasing values of mass of a spinning top that is increasing its velocity steadily towards " c ".
 
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  • #2
Do you mean 'rotates about its spin axis increasingly quickly'?

It might help if we make a simplifying assumption about the shape and distribution of (rest) mass in the top - how about a uniform cylinder? Another assumption - the cylinder is made of a perfectly inelastic, incompressible material. OK?
 
  • #3
Yes on

Do you mean 'rotates about its spin axis increasingly quickly'?

Any shape that you want - I am interested in the math and do not have a real or imagined object to "weigh".

" But we now understand that a spinning top weighs more than a top which is not spinning by a few parts in less than a billion. If the top spins fast enough so that the speed of the edges approaches 186,00 miles a second, the weight increase is appreciable-but not until then."
-Richard Feynman

Is there an equation that describes this?


thanks:smile:
 
  • #4
one approach ...

Suppose a top is made up of a set of nested, concentric rings. For your purposes, I guess a thin slice through the top, perpendicular to the spin axis, would be sufficient.

As the elementary ring spins faster (we're assuming it remains at the same distance from the spin axis), it will become more massive. If the outermost ring has a speed of ~0.866c, its mass increase would be 100%.
[tex]m = m_{0}/\sqrt{1-\frac{v^2}{c^2}}[/tex]

Integrate across all rings and you will have your formula (for one slice through the top; integrate across all slices for the whole top).
 
  • #5
Solution for cylinder

I took a crack at a solution for the rotating cylinder. Let the cylinder have a uniform mass density and a total rest mass of M0. Then the rest mass , Mrest, of the rotating cylinder (i.e. mass as measured in the zero momentum frame) is

[tex] M_{rest} = \frac {2M_{0}c^{2}}{R^{2} \omega ^{2}} [1 - \sqrt{1-(\omega R/c)^{2}][/tex]


Here is the calculation
http://www.geocities.com/physics_world/sr/rotating_cylinder.htm

Notice that as

[tex]\omega R << c[/tex]

the mass becomes

Mrest ~ M0
 
  • #6
NEREID

Nereid,

thanks for your help.

here's another HUGE problem in proving my theory that I'm working on-

What is the frequency (or wavelength) of magenta?

I have found lots of info on not knowing. I cannot buy the reasoning that the info is not available because it is a composite color. If the current R_G_B theory is right (I don't think so), then ALL other colors (on any Physics chart) are composite, and are neatly defined.

any help here?
 
  • #7
Magenta is composite.

You know about cones and how the human eye (and brain) perceives colour, right?

You also know about wavelengths of light and the rainbow, right?

So, if your eye can only send your brain three lots of information about colour (the intensity as seen in each of the types of cones), how come you can see six colours in a rainbow?

BTW, some women (but no men) actually have two different types of 'red' cones in their eyes. Those lucky enough to be born like this have a considerably richer perception of colours than the other women (and all men). :smile:
 
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  • #8
women like pink?

Nereid


OK, magenta is composite. I pre-stated that hoping to avoid some of the "middle" discussion, but let's have a go at this. I like to learn.

1. Does composite mean "a value of a combination of 2 or more things"?,

OR

2. Does it mean "that which can not be defined"?

AND

3. Are orange, green-blue (dk. turqoise), or indigo "composite" colors? -- I certainly thought they were, yet we have clearly defined values for these.

Maybe this is Quantum proof that man will never define/understand women.


LPF
 
  • #9
Does composite mean "a value of a combination of 2 or more things"?
Yes. If you looked at a chart of the intensity vs wavelength of a 'magenta' source, you'd see that it has (at least) two distinct peaks.

Are orange, green-blue (dk. turqoise), or indigo "composite" colors?
Not in the same way that magenta is. These colours are more like red, yellow, green, blue, and purple in that they are predominantly a narrow band of wavelengths. Of course, the English names of colours are imprecise; one person's 'purple' may be another's 'violet' :smile: However, with orange, green-blue, and indigo (maybe; I'm not sure what people mean by this one), it's easy to test - simply look at a rainbow (e.g. white light split by a prism; avoid something printed in a book, or on a computer screen) and see if you can see these three colours in the rainbow. If you can, then they're not composites.

You can also use this same test to show that magenta must be a composite colour - can you see it in a rainbow? If not, it can't be a pure colour!
 
  • #10
Originally posted by Nereid
Magenta is composite.

You know about cones and how the human eye (and brain) perceives colour, right?

You also know about wavelengths of light and the rainbow, right?

So, if your eye can only send your brain three lots of information about colour (the intensity as seen in each of the types of cones), how come you can see six colours in a rainbow?

BTW, some women (but no men) actually have two different types of 'red' cones in their eyes. Those lucky enough to be born like this have a considerably richer perception of colours than the other women (and all men). :smile:

Nereid, what are the "colors" of the three bands? I mean, rather than giving their spectral frequency or wavelength, could you estimate where they fall in terms of our color sense. And is there any online source you know about which discusses the details of the extra red band you spoke of, in particular how the enhanced color sense actually falls out in practivce. Psychometric studies? Seems like this distinction could give us at least a narrow window into the structure of the color sense.
 
  • #11
some women may have five!

Some sources for colours and bands, in general (probably gives you more than what you asked for) :
http://www.photo.net/photo/edscott/vis00010.htm
http://ergo.human.cornell.edu/studentdownloads/DEA350pdfs/vision.pdf
http://www.yorku.ca/eye/specsens.htm

Here's one article on the sex differences (looks like some women may have 5 different types of cones - blue, two green, and two red):
http://teachpsych.lemoyne.edu/teachpsych/faces/script/Ch09_HTM/color_vision.htm

How does this happen? The genes for cones are on the X chromosome, and women have two. What if the expression of a red cone in one cone is different from the expression of that in a neighbouring red cone?

SelfAdjoint: this thread doesn't really have much to do with TOE, maybe it could be moved? Or should a new thread be started?
 
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  • #12
Nereid,

Let me come at this from the backside-

Are there any colors other than magenta that we do not have freq./wavelength for?

It's my exerience that the answer is no, I have been able to identify every other color imaginable. They can all be found on THE chart ( or extrapolated). So, if magenta is a tertiary composite, then what are the peaks that you mentioned that produce it?

Note: I found MORE info on this topic in general in 3 NON-PHYSICS areas than from Physics specifc sources.

1. TV & computer monitor manufacturers. (reproducing color w/light)
2. Color copiers/printer manufactures. (color w/ inks)
3. Eyesight/medical

The latter provides some interesing data (apparently contradictory to your last post) The "red" cones actually percieve yellow @ peaks. Deep violet (395nm approx.) can not be produced by any combination of other colors. All eyes have evolved along the same route, I find it highly unlikely that females have a different # of such a basic, universal item. I think they're talking about having more feedback (nerve receptors) than males which allows them to "read" body language for danger, and sense what an unhappy baby needs through minute facial expressions. Also interesting- smaller diameter eyes see into UV range (cats,mice), and larger eyes can see into IR [whales,elephants (which also both communicate in ELF range of sound for long distances)].
No color is peceived in periphery vision, only movement (speed)


SelfAdjoint-
By the way, a true TOE is going to be as wide as it is tall. Physics is not the only branch of science that will benefit.


And lastly, magenta is seen in the rainbow, and green is only seen because of the "slit" shape the light comes through (dark-light-dark).


LPF
 
  • #13


Originally posted by Nereid

SelfAdjoint: this thread doesn't really have much to do with TOE, maybe it could be moved? Or should a new thread be started?

I'll start a thread in the biology subforum. The links you provided on the cone-gene linkage were very interesting, and I believe I now have a feeling for the bands and their content. I am also interested in the other end, that one of your links referred to, how the conscious sense of color is constructed in the brain. Does it happen in the visual cortex or somewhere else? What is recent and ongoing research focussing on? You know there are constantly reappearing arguments on the philosophy boards about qualia, and what they do or do not mean for a "reductive", or scientific account of consciousness. I feel that some acquainance with modern neurophysiology of color can help me hold up the scientific side in such discussions.
 
  • #14
Questions posted in Biology subforum

LPF -> You'll see that both SelfAdjoint and I have started new threads in the Biology subforum of PF. I'd encourage you to start a thread there with content similar to that of your last post here (women, what ranges of EM that other animals perceive, etc) - could be of significant interest.

SelfAdjoint -> I believe that colour perception - eye and brain - is an intensive area of research by brain scientists. As the system is perhaps more complex than touch, taste, and feel - and arguably the most important of the human senses - it may be a good one for philosophers to get their teeth into.
 
  • #15
Nereid,


Back to magenta. If this requires you to do work, I am not asking. A lead will suffice- somewhere to look, something to read. I don't care if it takes 8 composites to make it, what is its value?

If we evloved with the same rules (as unification demands), and ALL scientific observation must go through our eyes, then there can be no difference (except symmetrical mirroring) between our "perception", and what energy or matter is doing. Eyesight did not evolve randomly, it has to be an antenae to receive signals that already existed from moment One.
So far, all scientific? studies of light have observed what has already happened, and nobody has hypothesised on what IS happening. This does not require multi-dimensions, or multi-million dollar testing. They (portions of current theory) have been "red-shifted" into false assumptions. What happened to counter testing, testing under different conditions and environments, etc? (the anti-slit experiment).

I am not being "tricky" here, if the answer to my question is known to science, please direct me to it.


LPF
 
  • #16
magenta

..anyone...





LPF
 
  • #17
The problem with magenta of course is that it's a combination of bands from opposite ends of the visible spectrum, red and violet. Given that the brain forms its color categories by differencing of the three bands it inputs (see the threads in biology) this means the two extreme bands would difference to a low value and the differences with the central band would be high. Thus I think magenta is entirely a construction of the brain. More information might come from functional MRI studies of people as they saw and visulaized different colors.

I don't see that your metaphysics of seeing carries much weight. Also if you are going to get your information from people like TV tube manufacturers, you owe it to yourself to google up the work of Land (developer of the instant camera) who long ago was able to create a (washed out but genuine) full perceived spectrum using IIRC blue and red light. Fooled the brain you see.
 
  • #18
CIE chromaticity diagram

... such as on this page:
http://www.yorku.ca/eye/ciediag1.htm
give a pretty good idea of what's going on.

The 'pure colours' (narrow bands from the spectrum) lie on the curved line that is the border of the diagram. The straight line that forms the bottom connects the extremes of violet and red; nothing on this line is a pure color (except for the endpoints themselves).

It's easy to read and then quickly forget, but
*phospors can only represent colours within the triangle
*the colours printed (or displayed on your screen) are NOT the colours you'd see at any particular point in the diagram!
 
  • #19
photon emission

Nereid and selfAdjoint,

Thank you both for taking the time to reply! (I felt abandoned for a day or 2)

I sought out this forum, and the specific threads that I placed, with physics in mind. I mentioned the info gathered from tv, eyes, etc. because, after a long search, they had offered the most data. (Not all relevant)

What I was (am) really searching for is does the photon ever make an emission at the wavelength formerly known as "magenta"? This, of course, must be precluded by what the wavelength is, hence my original question.

Do either of you know of a good website that shows the spectral charts of all the elements?
I do not recall seeing magenta on any, the reds are always deep colored.

Also, do you know of other ways to measure wavelength of man made lights? (NOT through hot gas etc.) I would shine a blue light at "the machine", and it would read 460nm.

Or, last idea... computer generated (nor real) quanta of a combination of the colors required to make magenta spits out the magic answer for me... any such program exist?

I need to be sure it either doesn't exist naturally, or even if so, can we assign a value to it. I'm doing simple math, so the number (or the non-existance of it) is critical. Not knowing leaves me at an impasse.

LPF
 
  • #20
LPF: What I was (am) really searching for is does the photon ever make an emission at the wavelength formerly known as "magenta"? This, of course, must be precluded by what the wavelength is, hence my original question.

There is no single wavelength which, when perceived by the human eye, results in a colour perception called 'magenta'. To get magenta, you need at least some 'red' and some 'blue' photons.

LPF: Do either of you know of a good website that shows the spectral charts of all the elements?

This site has a quite nice Java applet showing the spectrum of various ionised elements:
http://www.colorado.edu/physics/2000/quantumzone/

To see what 'colour' the emission spectrum of an element is, you'd need to combine the lines (at the right strengths). There's probably a way to do it with a computer monitor, but it'd be tricky (from the CIE diagram you can see that single wavelengths - which is what each emission line is - are outside the triangle). Alternatively, you could just look at the flame in an atomic flame spectroscope! Much the same effect can be seen by sprinkling a salt of your favourite element into a gas flame - you've seen this I'm sure; when it's sodium chloride, the flame goes orange-yellow (from those very strong D lines).

LPF: Also, do you know of other ways to measure wavelength of man made lights? (NOT through hot gas etc.) I would shine a blue light at "the machine", and it would read 460nm.

Spectroscope, or spectrometer. As 'blue light' is surely a mixture of wavelengths, your spectroscope will show you a graph, with intensity vs wavelength. The display could be as fancy as you'd be prepared to pay for!
 
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  • #21
continued

Nereid:"There is no single wavelength which, when perceived by the human eye, results in a colour perception called 'magenta'. To get magenta, you need at least some 'red' and some 'blue' photons."

So, essentially, magenta will never show on spectroscopy because red and blue have their own separate identities (with other colors on both sides)


Nereid:"This site has a quite nice Java applet showing the spectrum of various ionised elements:
http://www.colorado.edu/physics/2000/quantumzone/ "

That is a very educational site, however, I came across a problem on their charts. The applet and the page on spectral readings did not match for Hydrogen. Being on the learning side of this curve, I do not know enough to say which one is accurate, and also doubted the accuracy of the rest of the chart (since they all stem from Hydrogen). I did e-mail them about this, but never received a response or saw a change on the web site.


Nereid:"Spectroscope, or spectrometer. As 'blue light' is surely a mixture of wavelengths, your spectroscope will show you a graph, with intensity vs wavelength. The display could be as fancy as you'd be prepared to pay for!

I have a home-made version (cd in a box with slit and viewing tube), however, how can I calibrate it for values that don't exist? Again, using the standard physics spectral chart of visible light, I have lines on the cd that match all values from violet to red. The only way to produce magenta is to allow for 2 cycles back-to-back. I had mentioned to you before of seeing magenta in a rainbow. A more exact description is between 2 rainbows (a double). So, by seeing this in nature, and producing it at home, I hope you can begin to sense my frustration that there is not even a theoretical value for this color. Especially when, in the high school physics book that I have, the 3 overlapping circle color chart (R-G-B) uses Y-M-C as their subtractive opposites. Without magenta, their whole diagram falls apart. "Me thinks I see spooky action in this uncertainty!"


LPF


PS - what would you recommend as THE best publication to submit papers on this sort of thing?
 
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  • #22
By the way, "We don't know" is certainly an exceptable answer to my question. Diverting the flow towards the limitations on MY (& not yours) perception is a political trick that could certainly be "perceived" as an insult to my intelligence. Human perception has been the gateway for all knowledge. The limitations of the current "model" of color exclude magentas' existence. To then defend the current model by assigning singularly unique and arbitrarily imaginative qualities to this color, while still allowing for it in other parts of science is baseless. Change the form of the chart from linear to circular, and we're all happy.


LPF
 
  • #23
No we're not. Your model disagrees with what DO KNOW about human perception of color. That was laid out for you and you disagree with it, but it still remains that that model is based on facts and experiments with PERCEIVING BRAINS and your is not.
 
  • #24
selfAdjoint,

I was only asking a couple of direct and specific questions about magenta. I was never answered, except to be directed somewhere else for asking such a dumb question. I do not disagree with any part of current perception of color theory. Asking for freq. or wavelength is a specific measurement, and has nothing to do with perception. It is a question regarding electro-magnetic wave value, and I thought a physics forum MIGHT be of some help.

LPF
 
  • #25
It would seem that they are trying to answer you as best they can. If they were to have given you a simple I don't know that wouldn't have been very helpful so it would seem as though they have given you what info they can which will hopefully help out instead.

Out of curiosity this wouldn't happen to have anything to do with the sorts of experiences P.K. Dick had would it? I think that it was light the colour of something like magenta or pink and he gave some sort of a value for it in VALIS I believe and said that it was off the spectrum to a particular end.
 
  • #26
stat.ape,

Yes, I know they both were helping, and I am grateful. There is a lack of emotion available in this format, and I can see after reading the entire thread again, that my last posts were blunt to the point of possibly taken as rude. I am certainly not here to make enemies, and will no doubt seek the assistance of Nereid and Selfadjiont in the future.

Nereid and Selfadjoint: please accept my appology if I have stepped on your toes too hard. I mainly just wanted to stomp on the ground like a child (frustration!)


The idea that there is not just one value for magenta is fine. I understand. Here's what I am looking for now:

Nereid: "Yes. If you looked at a chart of the intensity vs wavelength of a 'magenta' source, you'd see that it has (at least) two distinct peaks.

Can you give me the values of those peaks?

SelfAdjoint - while it may be hard to swallow, I am willing to work around the possibility that it only exists between our eyes, so to speak. So my next step is to try to get a "hypothetical" value. This is essentially an attempt to improve on the spectral chart of visible light. If the model is very good, I should be able to calculate it.

If moniters etc, use magenta to create other colors in a three color scheme, couldn't this color be ran through a spectrometer? (They don't know the answer either, by the way.) We can certainly produce it, and see it, why can't we measure it?!


LPF
 
  • #27
TheStatutoryApe,

By the way, I have not heard of PK Dick or "VALIS".


LPF
 
  • #28
Philip K. Dick was one of the greatest science fiction authors. The movies Blade Runner and Minority Report, among others were made from his work. His great theme was the problematic identity, Am I who I think I am? Or Not?

He had various problems with medications, and in his later books his identity themes were interwoven with hallucinations - or of course he would raise the questions, are they hallucinations or are they real? And if real, what do they mean to me? Valis, one of his very last, is a marvelous mystery tour of human experience. However bent Dick became, he always retained his story telling power.

His very best book, by common consent is The Man in the High Castle, an alternate history story in which Germany and Japan won World War II. But what he does with it is miles away from what, say, Harry Turtledove would do.
 
  • #29
Philip K Dick is a sci fi author. Now that I have spelled it out you may recognize the name, he wrote the book that Bladerunner was based off of and the short story that The Minority Report was based off of. At any rate, he wrote a book called V.A.L.I.S. in which he describes odd events that occurred in his life and certain experiences he believed he'd had. One of these experiences was sitting in his bed one night and having a pink laser light beam shot into his eye from no particular source. He said that it transmitted information directly into his brain and left him blind for a few days. At one point he talked about looking for the colour of the pink light on the spectrum and he and a friend decided that it fell outside the range of the visual spectrum. Your seemingly frenzied search for the value of magenta reminded me of that and not knowing where this all is going prompted me to ask.
 
  • #30
Ha! You type a lot faster than I.
 
  • #31
Hey Statutory! Glad we share a liking for Dick. I'll never forget reading those last books of his, and the weird mental states they put me into. No drugs, just Dick's stories.
 
  • #32
Maybe we can kill 2 birds with 1 stone. Stop young girls from wearing t-shirts that say "throw rocks at boys", etc. Have them wear ones that say "Just say No to Dick".




Thanks for the "reviews", I have never read sci-fi, so it's news to me.

I have definitely had a hard time with something that I thought would be answered from one posted question. Oh well.

I think this question is not important to the Big Boys upstairs. Color wheels are child's play. I'm just a "If it IS broke, then fix the Damn thing" kind of guy.


LPF
 
  • #33
i'm sorry but i have to ask. what do you need the magenta values for anyway?


perhaps the answer to your question lies in the direct approach? just tell them what
the real problem is and maybe it can be fixed. unless, of course, it requires a
non-disclosure agreement. but i, for one, promise not to tell.
 
  • #34
nine6,

The current color model is what is "broken". Every color imaginable (except magenta) can be described by a specific wavelength. If the model is broken , it is likely to cause misunderstandings down the line. The Photon is the most important, and least understood item in the Universe. I think starting with what you know is broken is a good place to begin.


LPF
 
  • #35
Magenta isn't the only color that isn't a simple frequency; think of chartreuse, teal, and various shades of orange. When it was discovered by chemists, puce was called a brand new color, and you would have trouble finding it in the spectrum.

A lot of your problem comes from ignoring saturation. The spectrum colors are usually shown fully saturated, while many of the colors we use in everyday life are pastels.
 

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