HDTenEightyP/NetNews huggingface dataset:
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: E=mc2?
Date: 31 Aug 92 10:40:37 GMT
Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands.

sajid@jam.wpd.sgi.com (Sajid Zia) writes:

>Can somebody write to me how Einstein arrived at this
>equation, I am extremely curious. Thanks,

I copy this directly from the book: Subtle is the lord, the science and
the life of Albert Einstein, by Abraham Pais. On page 148 he writes:

Einstein's proof of 1905 for the relation E=mc^2 runs as follows:
Consider a body with energy E_i at rest in a given inertial frame.
The body next emits plane waves of light with energy L/2 in a given
direction making an angle \phi with the axis and an equal quantity
of light in the opposite direction. After these emissions the body
has energy E_f, so that \Delta E=E_i-E_f=L. Consider the same situation
as seen fom an inertial frame moving with a velocity v in the x direction.
According to the equatiion

E'/E=\gamma(1-v cos(\phi)/c),

\Delta E'=E'_i-E'_f=\gamma L , independently of \phi. Thus:

\Delta E'-\Delta E=L(\gamma-1) [1], 

or, to second order:

\delta E'-\Delta E=(Lv^2)/(2c^2).

Now, Einstein said, note that [1] for the energy differential is identical
in structure to the equation for the kinetic energy differential of a
particle,

W=\int K'_x dx'=m\int_0^v \gamma^3 vdv=mc^2(\gamma-1),

so that `if a body gives off the energy L in the form of radiation, its
mass diminishes by L/c^2. The fact that the energy withdrawn from the
body becomes energy of radiation evidently makes no difference'.

******************************************************************** 
* J.C.A. Wevers                *         u\  _\       /e+        2 * 
* johan@blade.stack.urc.tue.nl *     1 |   \ u \  X  /         |   * 
******************************** P = - |    >   >---<     + ...|   * 
*     The only nature of       *     N |   /   /     \         |   * 
*     reality is physics       *         u/   /d     u\            *
********************************************************************
From: phfrom@nyx.uni-konstanz.de (Hartmut Frommert)
Newsgroups: sci.physics
Subject: Re: weak force
Date: 26 Aug 92 14:03:07 GMT
Organization: Dept. of Physics, University of Constance

nat@netcom.com (Nathaniel Stitt) writes:

>The articles I just read about the strong force are excellent!  [..]

Instead of I don't know which you mean (maybe I missed..) and since
nobody else answered...

>Ok, same question about the weak force: Is there a formula that describes
>the action of the weak force?

The weak (nuclear) force or weak interaction is mediated by the so-called
"intermediate" gauge bosons, i.e. W^{+/-} and Z^0. 

You can describe the action (in the Standard Model [GSW or 3-2-1]) of them
on the other particles in the theory by several formulae (here in TeX):

1. In the field equations of fermions and Higgs bosons, the W and Z appear 
   via the gauge covariant derivative, and a bit more complicated as 
   E/M current (of the W^{+/-} only) in the photon's FE.

2.a. In the momentum law, i.e. the eq of continuity for the other particles
   (or fermions only), their action can be seen on the right hand side
   as a product of their field strength with the week currents: this follows
   from the cont eq ( $T_.^.$ : covariant canonical energy momentum tensor;
   all calculations in Special Relativity)
   $$
   \partial_\nu T_\mu^\nu = 0
   $$
   by separation of $T_.^.$ in the "matter" part (of fermions, or all 
   particles BUT W and Z) and the "external" part of the W and Z bosons:
   $$
   \partial_\nu (T_m)_\mu^\nu = - \partial_\nu (T_e)_\mu^\nu =: k_\mu
   $$
   and insertion of the W- and Z- field eq's on the right hand side which
   is regarded here as a force (density) caused by the W and Z on 
   (fermionic) matter, where W and Z are treated as external fields.
     [Obviously this may be performed for arbitrary interactions]
   This gives
   $$
   k_\mu = \hbar [F^{W^{+/-}}_{\mu\nu} j_{W^{+/-}}^\nu + 
                  F^Z_{\mu\nu} j_Z^\nu]
   $$
   (there may be other constant factors depending on which def you take for 
   the Lagrangian and $j$). 
  b. Integrating over a spacelike 3-hypersurface yields the momentum law 
   (up to a boundary surface term)   
   $$
   (d/dt) P_\mu := (d/dt) \int d^3x (T_m)_\mu^0 = \int d^3x k_\mu =: K_\mu
   $$
   (also general, insert $k_\mu$ to get specific).

   Inserting all the complicated expressions for the $j$'s in the theory
   makes the eq of continuity and the momentum law look rather complicated,
   even if you consider point particles for simplicity.

Now, please decide which of the formulae you like most :-)
--
 Hartmut Frommert, Physics, Univ of Constance, | + Whale killing is murder. +
 P.O.Box 55 60, D-W-7750 Konstanz, Germany | + Eat whale killers, not whales.
 E-Mail: <phfrom@dknkurz1.bitnet> or <phfrom@nyx.uni-konstanz.de>
+    "Windows NoT" expands in German to "Windows Noch Teurer"
+                                                ^even   ^more expensive
From: Eric_S_Klien@cup.portal.com
Newsgroups: sci.physics
Subject: Re: Units (was Re: E=MC^2)
Date: Thu,  3 Sep 92 01:43:04 PDT
Organization: The Portal System (TM)
Distribution: world
  <mcirvin.715297106@husc8>

The best answer that I have received to my translation of one gram of 
matter into energy is the following: 
 
"   The "c" in E=mc^2 is the speed of light in the vaccum, which is 
the same everywhere and always (hence c, for Constant). It is, near 
enough, 3e8 (i.e. 300,000,000) meters per second, so c^2 is 9e16 
meters squared per seconds squared. Those are funny units, but when 
multiplied by mass they give units of energy. If the mass is one 
gram, the energy is (1e-3 kilograms) x (9e16 m^2/sec^2)= 9e13 Joules 
 
   One kilowatt-hour (the thing the power company charges you 4 cents 
for) is 3.6e6 Joules, so this is (9e13 Joules) / (3.6e6 Joules/kw-h) 
= 2.5e7 kW-hr, i.e. 25 million kilowatt-hours. Happy now?" 
 
Can anyone convert this into energy of sticks of TNT?
 
                                                           Eric Klien
From: mab@wdl39.wdl.loral.com (Mark A Biggar)
Newsgroups: sci.physics
Subject: Re: Inertial drive?
Date: 31 Aug 92 23:11:10 GMT
Organization: Loral Western Development Labs

In article <0fhS02Go20x701@JUTS.ccc.amdahl.com> drp40@cd.amdahl.com writes:
>An office mate recently mentioned having heard about something called
>an "inertial drive" which was an enclosed device with some sort of motor
>and geared arrangement which would produce a force in a single direction
>by converting rotational inertia into "linear" (??) inertia.  Sounds 
>pretty bizarre.  Anyone have any details on this?

This is the "Dean Drive" made famous in the early to mid 60's in
Analog Magizine.  General Opinion is that it was a fake.  Dean applied
for patents but no one has been able to reproduce the effect since. 
Because Dean would not let anyone else touch his prototype one one was able
to perform the obvious experment of suspending it from wires and seeing if
it didn't hang straight (if it hangs displaces sideways and doesn't occilate
then it is producing a unidirectional force).  For a possible explaination
of how it could work see references to "Davis" mechanics which proposes
that there is an additional force law like Newtons involving forces 
proportional to changes in acceleration (called jerk).  Modeling using 
"Davis" machanics shows that it is very unlikely the a mechanical device
such as Deans could work, but suggest that driving a plasma in a tube
using the proper frequency saw-tooth wave might work (See the novel
"Stardriver" by Lee Corey for a fictional account based on this idea).

--
Mark Biggar
mab@wdl1.wdl.loral.com
Newsgroups: sci.physics,sci.environment,misc.consumers
From: betel@camelot.bradley.edu (Robert Crawford)
Subject: Re: Radioactivity and Superstition; was: Re: Are Your Light Bulbs Radioactive?
Organization: Bradley University
Date:  4 Sep 92 13:46:40 GMT

de5@ORNL.GOV (Dave Sill) writes:
>>I stand corrected by John De Armond.  I believe his figures, but I'll
>>undercut his price.  I'll eat as many as Jym Dyer will supply at a mere
>>$5k a bulb.  See Jym, we capitalists really do compete.
>If the threat is as insignificant as you say, why not do it for a nominal fee?
>$5000/bulb is awfully high for a threat supposedly on a par with a banana.

	Regardless of the health threat, there is the fact that it's
unpleasant to force feed yourself bits and pieces of light bulbs.
However, I am willing to do it for $2.5k...


--
"It's not the size of the boat; it's the motion of the ocean."
        --- Tom Servo

Robert Crawford 			betel@camelot.bradley.edu
From: sichase@csa1.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Units (was Re: E=MC^2)
Date: 3 Sep 92 18:49:12 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa1.lbl.gov
NNTP-Posting-Host: 128.3.254.196
News-Software: VAX/VMS VNEWS 1.3-4   

In article <65184@cup.portal.com>, Eric_S_Klien@cup.portal.com writes...
>"   The "c" in E=mc^2 is the speed of light in the vaccum, which is 
>the same everywhere and always (hence c, for Constant). It is, near 

That's right.  That's Constant, as in Constantine.  This Roman emperor,
mostly known for bringing Christianity to the Roman empire, actually made
the first measurement of the speed of light by measuring the speed of light
travel time back and forth across the Colosseum one day when he got bored
of watching the gladiators mutilate one another.

If you don't believe that:

"c" is for celetaris, Latin for "speed" (whence the English "celerity" and
"acceleration.") My Latin is poor, so I may have spelled celetaris incorrectly.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: sci.physics
From: seove@mars.lerc.nasa.gov (ERIC OVERTON)
Subject: Quarks, Neutrons, and Mesons...
News-Software: VAX/VMS VNEWS 1.41    
Organization: NASA Lewis Research Center
Distribution: usa
Date:  2 Sep 1992 15:47 EDT  

"Quarks, Neutrinos, Mesons.  All those damn particles you can't
see.  That's what drove me to drink.  But _now_ I _can_ see them!"

-- S. Harris
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: abot Maxwell's demond
Date: 2 Sep 92 22:01:11 GMT
Article-I.D.: husc8.mcirvin.715471271

junipero@academ01.mty.itesm.mx (Junipero Rodriguez Rivera) writes:


>  Where can i find about Maxwell's demon??? or
>where can i find in this net about american scientist (jan-70, jan 71)

One nice place to read about it is in volume II (I think) of the
Feynman Lectures on Physics.  Feynman discusses thermodynamics
in general and includes some enlightening discussion of what
irreversibility means.
-- 
Matt McIrvin, Cambridge, Massachusetts, USA
From: balbes@ohstpy.mps.ohio-state.edu
Newsgroups: sci.physics
Subject: Re: LaTeX submission to Phys. Rev. ?
Date: 27 Aug 92 14:31:15 EDT
Distribution: na

In article <1992Aug27.170256.26054@noose.ecn.purdue.edu>, tekman@ecn.purdue.edu (Erkan Tekman) writes:
> By the way, you may also send figures via e-mail if you have them in
> postscript format (not the encapsulated one, though).

When did this happen?  The insert published a few months ago
said they were working on it but couldn't yet accept postscript.
Xref: sparky sci.physics:14016 alt.sex:28268
From: cowan@aqua.ocunix.on.ca (Darin Cowan (root))
Newsgroups: sci.physics,alt.sex
Subject: Re: BAROMETERS (was Re: Subject?)
Date: Wed, 02 Sep 92 23:40:56 GMT
Organization: The Aquarium, Ottawa, Ontario

zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes:

> You are taken to a large, impressive-looking office building.  You may
> wander the building and its environs at will <etc. etc.> You are given
> an accurate barometer.  Your task is to determine the height of the
> building.
> 
> Name at least six ways to accomplish this task. [before breakfast! ;-]

1) Measure your shadow in terms of 1 barometer length (outside).  Measure
the building's shadow in barometer lengths.  Calculate the building's
height from the ratio given that you know your own height.

2) Present the barometer to the local building inspector as a "gift".
Ask him to pull the file on the building plan as a favour, read the
height from the documentation.

3) Drop the barometer off the roof and time how long it takes to hit
the ground.  Calculate the height from known formulae.

There's 3 ways.

ObSex:  Pussy tastes better than asparagus too :-)


==============================================================================
                      cowan@aqua.ocunix.on.ca
  The Aquarium BBS  (613)736-1481  2400-14400 bps  V.32bis  V.42bis  HST
==============================================================================
Newsgroups: sci.physics
From: barry@arnold.math.ucla.edu (Barry Merriman)
Subject: Re: Report on Philosophies of Physicists
Organization: UCLA, Mathematics Department
Date: Thu, 3 Sep 92 04:03:50 GMT

In article <2634@news.cerf.net> mitsu@nic.cerf.net (Mitsuharu Hadeishi) writes:
> 


>  The standard Western boolean logic is
> clearly an approximation; not even a very good one in many cases.
> Because Eastern philosophy subsumes "ordinary" logic as a subset,
> it happens to be quite adequate to deal with both classical and
> quantum physics.
> 
> Mitsu

The above is all at the most metaphorical level. Is there any situation
in the experience of the Eastern philosophers in which boolean logic 
was strictly violated? (I.e. a situation precise enough to be
cast into predicate logic, in which the logical operators did
not work properly). I think not. Therefore we conclude they were
either very interested in non-logical modes of thought, or they
incorrectly understood what boolean logic was (quite likely).

What this has to do with QM is not clear to me.



--
Barry Merriman
UCLA Dept. of Math
UCLA Inst. for Fusion and Plasma Research
barry@math.ucla.edu (Internet; NeXTMail is welcome)
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: Impure Mathematics
Date: 28 Aug 92 17:28:14 GMT
Article-I.D.: ruhets.Aug.28.13.28.14.1992.13802
Distribution: na
Organization: Rutgers Univ., New Brunswick, N.J.

Scott Chase writes:
>I agree with everything you wrote, even the parts I have omitted.  But I
>still object to someone jumping in to censor other people's postings.
>Maybe this person had a well-reasoned argument to make in defense of her
>position that rape should never be the subject of humor - especially in
>male-dominated crowds in which women are already uncomfortable.
>So then let her make the argument in public [ ... ]

Disclaimer: I never saw the original posting, nor Suzanne's comments
[except quoted fractions] - but I think I saw the offending bit of
"humor" a few years ago, it sounds familiar.

What I wanted to say is, does Suzanne really need to make a well-
reasoned argument that jokes about rape aren't funny?  Just sit back
and think about it for a moment.  They're _obviously_ not funny, and
people who can't figure that out are probably beyond hope.

Given how common such offensive behavior is (not to mention the
commonness of actual rape) I can see how someone could get fed up.
Men in male-dominated fields can get even more isolated than most
from what signals they are sending, so they ought to be extra
careful.  Hence the reason I'm posting this to sci.physics.
Newsgroups: sci.physics
From: msb@sq.sq.com (Mark Brader)
Subject: Re: BAROMETERS (was Re: Subject?)
Summary: I've just invented a new solution, but this Summary line is too narrow
Organization: SoftQuad Inc., Toronto, Canada
Distribution: na
Date: Thu, 3 Sep 92 23:13:48 GMT

> In addition, the graduations on the face of the barometer can be used 
> to assist in making angle measurements, since those in one quadrant 
> can be mapped onto 90 degrees. 

Ah, he assumes it's an analog barometer.  For balance, let's assume it
isn't.  Now place a board on the ground and cover it with closely spaced
dead-end wires, which are alternately connected to two terminals, like this:

        +-----------------------------------------------------
        | -----------------------------------------------------+
        +----------------------------------------------------- |
        | -----------------------------------------------------+
        +----------------------------------------------------- |
        | -----------------------------------------------------+
        +----------------------------------------------------- |
        | -----------------------------------------------------+
   <----+----------------------------------------------------- |
          -----------------------------------------------------+--->

Set up a timer circuit so that anything making an electrical connection
between the terminals will stop the timer.  Go to the roof and there set
up a pair of contacts a small distance apart, so that anything making an
electrical connection between them will start the timer.  [The connection
between the ground and rooftop circuits had better be through a radio
link, since you don't know the height of the building. :-)]

On the roof, break the barometer open and catch the mercury.  Pour it
between the rooftop contacts so that it lands on the ground contacts.
Correct for atmospheric resistance and compute the height.

Best performed on a calm day!
-- 
Mark Brader			"Great things are not done by those
SoftQuad Inc., Toronto		 who sit down and count the cost
utzoo!sq!msb, msb@sq.com	 of every thought and act."  -- Daniel Gooch

This article is in the public domain.
Newsgroups: sci.physics
From: doug@netcom.com (Doug Merritt)
Subject: Re: Axiom of Physics
Date: Thu, 27 Aug 92 06:23:55 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Distribution: na

In article <mcirvin.714873508@husc8> mcirvin@husc8.harvard.edu (Mcirvin) writes:
>  The constancy of c is usually taken as an axiom of relativity  [...]
>  One could still construct a completely
>different theory with a different set of axioms, though it would
>be wrong as a description of reality.

Not quite. A different axiom or set of axioms can, and very frequently *has*,
been used, with the invariance of c then being a derived theorem rather
than an axiom.

This is nitpicking, since it's simply a side effect of the fact that
there are always an infinite number of ways of constructing equivalent
models (up to isomorphism :-) of axiomatic systems.

I happen to think it's an important nitpick, though, both in general
and because there are so many fruitful ways that people have come up with
to axiomatically derive Special Relativity.
	Doug

-- 
Doug Merritt	Preferred: doug@netcom.com   (or: doug@eris.berkeley.edu)
Professional Wild-eyed Visionary	Member, Crusaders for a Better Tomorrow
Newsgroups: sci.physics
From: brahm@cco.caltech.edu (David E. Brahm)
Subject: Re: Why do protons outnumber antiprotons?
Summary: Baryogenesis at the Electroweak Phase Transition
Organization: California Institute of Technology, Pasadena
Date: Wed, 2 Sep 1992 02:38:24 GMT

sichase@csa1.lbl.gov writes:
> [Sakharov's 3 conditions for generating a baryon asymmetry:
>   1) Baryon violation   2) CP violation   3) Thermodynamic Nonequilibrium]
> There is no baryon-number (B) violation in the Standard Model by itself.
> Only in the framework of grand unified theories (GUTs) ... does B
> violation become a part of the extended SM.

Not true.  Though the Standard Model conserves B classically (no terms in
the Lagrangian violate B), quantum effects allow the universe to tunnel
between vacua with different values of B.  This tunneling is _very_
suppressed at energies/temperatures below 10 TeV (the "sphaleron mass"),
_may_ occur at e.g. SSC energies (controversial), and _certainly_ occurs at
higher temperatures.

One possible scenario people (like me) study is that baryogenesis occurred
at the Electroweak Phase Transition (EWPT), the time when the Higgs field
first acquired a non-zero vev (T = 100 GeV or so).  A major problem, in
fact, is that there may be _too_much_ B-violation in the Standard Model, so
that after the EWPT is complete (and condition 3 above is no longer
satisfied) any previously generated baryon asymmetry would be washed out.

Curiously, it is actually condition (2) where the Standard Model fails;
there is CP-violation in the Standard Model, but not enough to produce the
baryon asymmetry we see today.

--
Staccato signals of constant information,  |  -- David Brahm
A loose affiliation of millionaires and    |  (brahm@cco.caltech.edu)
  billionaires and Baby ...                |---------------------------
These are the days of miracle and wonder,  | Disclaimer:  I only speak
And don't cry, Baby, don't cry, don't cry. |   for the sensible folks.
From: heading@breeze.rsre.mod.uk (Anthony Heading)
Newsgroups: sci.physics
Subject: Heat generation - a minimum principle?
Date: 26 Aug 92 15:55:22 GMT
Reply-To: heading%hermes.mod.uk@relay.mod.uk
Organization: Defence Research Agency

Feynman, in his Lectures in Physics (II 19-14), says "In a note
added after the lecture":

  Among the minimum principles that I could mention, I noticed
  that most of them sprang in one way or another from the least
  action principle of mechanics and electrodynamics. But there
  is a class that does not. As an example, if currents are made
  to go through a piece of material obeying Ohm's law, the
  currents distribute themselves inside the piece so that the
  rate at which heat is generated is as little as possible.

I've thought about this for a while, and I can't see how to
derive it or where it comes from. It seems to allow for the
solution of current distribution problems without explicitly
having to introduce the idea of a voltage potential field...

It must surely be equivalent to the ordinary del^2 phi = 0
model - can anyone show me how to derive it?

Anthony

-- 
Anthony Heading  (heading@hermes.mod.uk)
DRA Malvern, UK
Any opinions expressed are my own and in no way
represent those of my employer or any other organization.