HDTenEightyP/NetNews huggingface dataset:
From: firth@sei.cmu.edu (Robert Firth)
Subject: Re: Rotating Bucket of Water in a Gravitation Field
Organization: Software Engineering Institute
Date: Mon, 31 Aug 1992 19:00:30 GMT

In article <1992Aug31.231944.89940@physics.monash.edu.au> voros@physics.monash.edu.au (Joe Voros) writes:

>Many moons ago, yes.  Also, that if the bottom of the paraboloid just
>touches the bottom of the bucket, that the amount of water left in the
>bucket is exactly half, if it was full to begin with.

I don't remember that.  Gee, let the bucket have height h and radius w,
for a total volume pi.w^2.h.  The paraboloid has the apex at 0,0,0 and
intersects the circle of radius r=w at z=h, giving a surface defined by

	z = hr^2/w^2

The volume element under the surface (the water) is therefore

	dv = 2pi.r.z.dr = 2pi.h^2/w^2 .r^3.dr

and integrating between 0 and w gives

	2pi.h^2/w^2.w^4/4 = (1/2)pi.w^2.h, QED

Neat.  It's three dimensional, but if you use cylindrical polar
coordinates, theta drops out due to the symmetry, and you can work
with r and z alone.
From: ghenzie@phad.hsc.usc.edu (Gregory M. Henzie)
Newsgroups: sci.physics
Subject: Magnetic Resonance and T1
Date: 30 Aug 1992 19:00:25 -0700
Organization: University of Southern California, Los Angeles, CA
NNTP-Posting-Host: phad.hsc.usc.edu



Well, my last post got screwed up so here I go again.

Why does T1 for a substance typically increase with increasing magnetic
Xref: sparky sci.physics:13772 sci.environment:10919 misc.consumers:15809
From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.physics,sci.environment,misc.consumers
Subject: Re: Radioactivity and Superstition; was: Re: Are Your Light Bulbs Radioactive?
Date: 29 Aug 92 00:06:26 GMT
Organization: University of Washington, Seattle

In article <l9ns6oINNmol@utkcs2.cs.utk.edu> de5@ORNL.GOV (Dave Sill) writes:
>In article <1992Aug26.195524.25813@athena.cs.uga.edu>, mcovingt@athena.cs.uga.edu (Michael A. Covington) writes:

>>A child's environment is _full_ of things that are dangerous if ingested.

>Few of which are radioactive, since most folks don't have concentrated sources
>laying around their house...unless they have smoke detectors or compact
>flourescents.  Which is *exactly* the point the originator of this thread was
>trying to make.  Radioactivity *is* a different kind of threat than most
>parents are used to dealing with. 

	This is not true; ALL organic foods are radioactive (carbon-14,
remember?), and potassium contains 0.01% of K-40... so an eight-year-old
child (just about hammer-wielding age) has a 'safe and adequate'
recommended dietary intake of circa 1 gram of potassium per day...
which comes to about two microcuries.

	My cold fluorescent bulbs have less than one-hundredth of
that much radioactive material as a start initiator; this amount
of material poses no credible radiation threat to my health.

	The labeling of the lamps is intended to certify that the
amount of material present is not hazardous (and the 'radiation
hazard' trefoil symbol is not used in consequence). 

	John Whitmore

"When in doubt, run the numbers through... sometimes even just
one or two orders of magnitude can make a difference."
Newsgroups: sci.physics,sci.environment,misc.consumers
From: de5@ORNL.GOV (Dave Sill)
Subject: Re: Radioactivity and Superstition; was: Re: Are Your Light Bulbs Radioactive?
Organization: Oak Ridge National Lab, Oak Ridge, TN
Date: Fri, 4 Sep 1992 12:59:11 GMT

In article <JMC.92Sep3224636@SAIL.Stanford.EDU>, jmc@SAIL.Stanford.EDU (John McCarthy) 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.

-- 
Dave Sill (de5@ornl.gov)           For every Bill Joy there is a Kirk McKusick.
Martin Marietta Energy Systems     For every Bill Gates there is a Richard
Workstation Support                Stallman.                     --Paul Graham
Newsgroups: sci.physics
From: bryson@nas.nasa.gov (Steve T. Bryson)
Subject: Visuzlization '92 call for student volunteers
Organization: Applied Research Office, NASA Ames Research Center
Date: 3 Sep 92 14:05:51
Distribution: sci.physics sci.math sci.virtual-worlds sci.astro comp.human-factors comp.graphics.visualization comp.graphics



   Visualization '92 and the 1992 Boston Workshop on Volume Visualization
			
	****	CALL FOR STUDENT VOLUNTEERS		****

1992 Boston Workshop on Volume Visualization:	
		   Oct 17 and 18 1992, 	       Boston, Mass.
Visualization '92: 
		   Oct 18 through Oct 23 1992, Boston, Mass.

The Visualization '92 conference and the 1992 
Boston Workshop on Volume Visualization are seeking student volunteers. 
Volunteers will work  twenty hours or less in exchange for
complete free registration in the conference.  As the two
conferences are being held at the same location on
successive dates, the same students may volunteer  for both
conferences.  Come learn about the state of the art in 
volume visualization and the use of computer graphics to
study complex scientific phenomena.  

Student volunteers will be responsible for their own
transportation and lodging for the conferences.  To assist
in costs, limited shared rooms will be made available on a
first-come first-serve basis.  All students who are enrolled
full time in the fall 1992 are eligible.  

For more information, send dates of availability and 
field of study to:

For Visualization '92:
	Steve Bryson
	MS T045-1
	NASA Ames Research Center
	Moffett Field, Ca. 94035-1000
	(415) 604-4524 fax: (415) 604-3957
	bryson@nas.nasa.gov

For the Workshop on Volume Visualization:
	Roni Yagel
	Department of Computer and Information Science
	The Ohio State University
	228 Bolz Hall
	2036 Neil Av. Columbus, Ohio 43210-1277
	(614) 292-0060, fax: (614) 292-2911
	yagel@cis.ohio-state.edu




--

Steve Bryson
MS T045-1
NASA Ames Research Center
Moffett Field, Ca. 94035
(415) 604-4524
bryson@nas.nasa.gov

Newsgroups: sci.physics
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Subject: Re: Length scales in physics 4 - the Planck length
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Thu, 27 Aug 1992 17:35:00 GMT

matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes...
>All right, I guess you can call this "treating spacetime as a field".
>But then it would seem that string theory indicates that nothing weird
>happens to spacetime at small lengths: you always have a well-defined
>target space.

The question becomes something like: at what scale do fluctuations in
the metric become important.

Also, I don't know if you would call compactification wierd.

Dave Ring
dwr2560@zeus.tamu.edu
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Electrons in the body
Date: 26 Aug 92 19:44:35 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa3.lbl.gov
NNTP-Posting-Host: 128.3.254.198
News-Software: VAX/VMS VNEWS 1.3-4   

In article <1992Aug26.122949.10900@relay.nswc.navy.mil>, bwallet@apssgi.nswc.navy.mil (Brad Wallet) writes...
>Could anyone give me a rough estimate of the percent of mass of a human
>body which is made of electrons?  Not important, just curious.
> 
>Brad
>No ideas, no thoughts, no observations, no disclaimer

1/4000, more or less.  This is because an electron weighs 1/1836 of a proton
mass.  There is roughly one neutron for every proton in the body (very few
heavy elements with higher neutron/proton ratio are in any abundance in the
body.)  So there is one electron for every two nucleons.  

-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: mcwhirtj@unvax.union.edu (Jim Mcwhirter)
Subject: Re: Low Temperature (T=4K) LEDs
Organization: Union College, Schenectady, NY
Distribution: na
Date: Tue, 1 Sep 1992 19:42:07 GMT

Kevin,
I don't have a definitive answer, but keep trying.  I checked with
a friend whom I recalled having used an LED at 4.2K.  He said that
the LED he used was given to him by a researcher at IBM, and that 
it was  an off the shelf, vanilla LED out of their stockroom.  
So they do exists.  You probably should make up a rig for quick testing
and collect a dozen or so different types (assuming know one else
gives you a definite answer).

Jim McWhirter
Physics Dept.
Union College
Schenectady, NY
mcwhirtj@unvax.union.edu
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: Axiom of Physics
Date: 27 Aug 92 08:59:27 GMT
Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands.

frisinv@alleg.edu writes:

>I maintain that the conservation of mass/energy is an axiom.

The conservation of energy is the simple result from the laws of physics
being invariant w.r.t. the choise of the beginning point in time.
E.g. as you transform the time coordinate t -> t+a, then all the physics
will remain the same.

In general, all conservation laws can be derived from some symmetry:
The conservation from momentum can be derived from the invariance
from the physican laws w.r.t. (x,y,z)->(x+a,y+b,z+c), charge conservation
can be derived from the invariance from the Maxwell equations (or the
QED lagrangian density) w.r.t. gauge transformations, etc.
 
******************************************************************** 
* 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\            *
********************************************************************
Newsgroups: sci.physics
From: danforth@riacs.edu (Douglas G. Danforth)
Subject: Re: Uncertainty Principle
Organization: RIACS, NASA Ames Research Center
Date: Fri, 4 Sep 92 17:24:33 GMT

In <5273@tuegate.tue.nl> johan@blade.stack.urc.tue.nl (Johan Wevers) writes:

>prim!dave@germany.eu.net (Dave Griffiths) writes:
>>

>>Does it make any sense to talk about a particle having an unknowable, but
>>precise, position and momentum (which would be the case if the problem was
>>simply one of measurement)?

>Yes, but it is trickey. This is exactly the point the EPR experiment was
>pointing on. Aspect's experiments prooved that this interpretation
>should be handled with care, but some non-causal or non-local hidden-
>variable theories exist which reproduce QM.

>>Dave Griffiths

>* J.C.A. Wevers    

Aspect's detectors were inefficient (less than 1%).  A local realistic
theory can be constructed that gives the QM correlations for detector
efficiencies up to 81.8%.  The death of local theories is still premature.

-- D. G. Danforth

Newsgroups: sci.physics
From: rlbell@knuth.uwaterloo.ca (Richard Bell)
Subject: Re: The dangers in microwaved food...
Organization: University of Waterloo
Date: Wed, 26 Aug 1992 17:59:04 GMT

In article <20821@nntp_server.ems.cdc.com> mstemper@ems.cdc.com writes:
>In article <1992Aug20.200552.12599@elroy.jpl.nasa.gov>, david@euclid.JPL.NASA.GOV (David Bernath) writes:
>|> 
>|> >>In article <1992Aug20.015531.7842@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
>|> >>there are serious health risks in eating.
>|> >
>|> >There are serious health risks.
>|> 
>|> Health is a serious risk.
>
>Risk is healthy.
>

Life is a sexually transmitted disease, and Health is the slowest rate at
which one can die.

Xref: sparky sci.physics:13557 sci.skeptic:15014 alt.folklore.science:3147
From: rubinoff@linc.cis.upenn.edu (Robert Rubinoff)
Newsgroups: sci.physics,sci.skeptic,alt.folklore.science
Subject: Re: The dangers in microwaved food...
Date: 26 Aug 92 03:51:56 GMT
Followup-To: sci.physics
Distribution: na
Organization: University of Pennsylvania

The biggest danger from microwaved food is that you might eat too much of it
and become dangerously obese.

The second biggest danger is that you might eat too much unhealthy food (too
much fat, salt, etc.) 

The third biggest danger is that you might accidentally pull the door too hard
and drop the microwave on your feet.

   Robert

Disclaimer: all statements in this posting are incorrect.
From: jfreter@triton.unm.edu (The Myth)
Newsgroups: sci.physics
Subject: photons and gravity
Date: 3 Sep 92 22:05:48 GMT
Distribution: na
Organization: University of New Mexico, Albuquerque

I have a question that has been bugging me for many years since I took
my first astronomy and physics classes.

We know that photons have energy and carry momentum.  We also know that
these photons are deflected by gravity.  Even though photons have zero
rest mass, you can calculate an effective mass for any photon (a function
of frequency).

Since the photons are attracted by gravity can a massive object (like a
person or planet) be attracted to the photon?  That is, can the photon
flux in the universe be enough to close the universe?  Or am I way off
in my reasoning?
From: matt@physics16.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Facts and Values (was Where it came from)
Date: 25 Aug 92 14:07:38
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
Distribution: na
	<25623@dog.ee.lbl.gov> <1992Aug21.094831.7995@u.washington.edu>
	<13497.2a9a1cc6@ohstpy.mps.ohio-state.edu> <25732@dog.ee.lbl.gov>
	<schinder.714773737@leprss.gsfc.nasa.gov>
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics16.berkeley.edu
In-reply-to: schinder@leprss.gsfc.nasa.gov's message of 25 Aug 92 20:15:37 GMT

In article <schinder.714773737@leprss.gsfc.nasa.gov> schinder@leprss.gsfc.nasa.gov (Paul J. Schinder) writes:

> >(3) 1 year = 10^7 seconds
> 
> Probably because it's a little more important to astrophysics to get
> closer to the right number, astrophysics grad students learn that 1
> year = pi x 10^7 sec (which is almost right).  Along with pi^2 = 10,
> it comes in very useful.

Actually, Scott was just slightly imprecise; what he should have said
is that every high-energy grad student learns that one year is 10^7
seconds.  

This is more nearly correct that pi x 10^7 seconds; the point is that
in one calendar year, it is realistic to assume that you will be
taking data for about 10^7 seconds.
--
Matthew Austern                   Just keep yelling until you attract a
(510) 644-2618                    crowd, then a constituency, a movement, a
austern@lbl.bitnet                faction, an army!  If you don't have any
matt@physics.berkeley.edu         solutions, become a part of the problem!
Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: FTL Microwave Signal
Organization: University of Virginia
Distribution: na
Date: Wed, 26 Aug 1992 23:41:31 GMT

In article <1992Aug26.202707.15463@bnr.ca> bucknerb@bnr.ca (Brent Buckner) writes:
>In article <25777@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>>In article <1992Aug26.021649.4507@augean.eleceng.adelaide.edu.AU>, dabbott@augean.eleceng.adelaide.edu.AU (Derek Abbott) writes...
>>
>>I think that the point is that if even one bit of information is transmittable
>>FTL, then we will all go off in search of the correct reformulation of
>>mechanics.  If we then find such a theory, we presumably would *then*
>>know how to exploit the effect in a serious way.
>>
>
>Here's a set of assumptions under which the effect could be
>useful:
>
>1.  We can usefully transform the FTL data transfer into backward-
>    in-time data transfer (essentially, given that the transfer is from
>    A to B, then we can put A and B into sufficiently
>    different frames of reference).

     This assumption makes absolutely no sense if we are in possession
     of a signal that goes faster than light.   Under those circumstances,
     the assumptions that underlie the theory that gives rise to 
     backward in time behavior are incorrect.

>2.  We only get closed timelike loops.

     Similar problem.  Timelike makes sense in a SR (or GR) formulation.
     It does not make much sense if one can exchange signals faster
     than the assumed limiting speed.  Assuming the 'new' limiting
     speed is infinite, we could just coordinatize using the 'new' 
     assumption and arrive at a Galilean relativistic frame in which
     there is no such thing as a 'closed timelike loop'.

>3.  Atomic decay is non-deterministic.
>
>Let's say that we can send a bit backward in time an hour
>(see assumption 1).
>Further, you've got a question that you want answered _now_,
>that your computer can verify within fifty minutes.

     The point is, that the assumptions by which we arrived at
     the 'backward in time' behavior of FTL signals are invalidated
     by the existence of causal FTL signals and thus the theory
     would be incorrect.

                         dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Facts and Values (was Where it came from)
Date: 25 Aug 92 20:42:27 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa3.lbl.gov
NNTP-Posting-Host: 128.3.254.198
News-Software: VAX/VMS VNEWS 1.3-4   

In article <13497.2a9a1cc6@ohstpy.mps.ohio-state.edu>, balbes@ohstpy.mps.ohio-state.edu writes...
>> Values do indeed effect how we do our daily work as scientists.  No doubt
>> about it.  But, at least in the long run, they have no effect upon the
>> science itself.  What human values are expressed by E^2 = m^2 + p^2?  
> 
>The human value of c=1.  :-)

Among the rules that every graduate student in HEP knows are
(1) c = 1
(2) c = 1 foot/nanosecond
(3) 1 year = 10^7 seconds
(4) a proton weights 1 GeV (see rule (1)) 
(5) All computers are too slow.

Only (1) and (5) are strictly true.

-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
From: bwallet@apssgi.nswc.navy.mil (Brad Wallet)
Newsgroups: sci.physics
Subject: Electrons in the body
Date: 26 Aug 92 12:29:49 GMT
Organization: Cruise Missile Weapons Systems, Naval Surface Warfare Center

Could anyone give me a rough estimate of the percent of mass of a human
body which is made of electrons?  Not important, just curious.

Brad
No ideas, no thoughts, no observations, no disclaimer
From: jscott@winvmc.VNET.IBM.COM (Jonathan Scott)
Newsgroups: sci.physics
Subject: Re: Is the Action a Component of a more general object?
Date: 1 Sep 92 14:42:41 GMT

In <1992Aug20.173955.89822@physics.monash.edu.au> Joe Voros writes:
>As I was musing with Feynman's path integral approach to QM, I wondered
>if the action S is a component of a more general object.  What I have in
>mind is something analogous to the energy being connected with the
>time-time component of the energy-momentum tensor.  Does anyone know of
>anything at all related to these musings?  Work? References?  Ideas?
>--
>Joe Voros
>Department of Physics, Monash University, Clayton, VIC, 3168, Australia.

In complex four-vector algebra (or spin-vector algebra or octonions or
whatever you call it), the action is the scalar part of the four-vector
product x p* (where the * denotes changing the sign of the space-like
components, like raising or lowering tensor indices).  In terms of
conventional components, it can be written as Et - p.x where p and x are
three-vectors.  The real vector part of the same quantity is the Lorentz
momentum Ex - tp, and the imaginary vector part of the same quantity is
-ix cross p, giving the angular momentum.  When no external forces are
acting, both vector parts are constant.  Note that the constancy of the
Lorentz momentum expresses more then conservation of linear momentum, in
that it also says that mass cannot disappear from one place while
reappearing with the same momentum somewhere else.

If anyone knows what the imaginary scalar part of the same quantity is,
I'd like to know.  Its value for the neutrino and electron is +/- hbar/2
(with opposite signs for the antiparticles) and it seems to be something
like isospin, but it's absolutely conserved, just like the imaginary
vector part, angular momentum.

Jonathan Scott
jscott@winvmc.vnet.ibm.com
Xref: sparky sci.physics:14032 alt.sex:28285
From: jac@ds8.scri.fsu.edu (Jim Carr)
Newsgroups: sci.physics,alt.sex
Subject: Re: BAROMETERS (was Re: Subject?)
Date: 3 Sep 92 14:31:51 GMT
Reply-To: jac@ds8.scri.fsu.edu (Jim Carr)
Followup-To: sci.physics
Distribution: na
Organization: SCRI, Florida State University

In article <1992Sep2.172157.14850@linus.mitre.org> m14494@mwvm.mitre.org (Mike White) writes:
>The Myth writes:
>>> Your task is to determine the height of the building [given a barometer]
>
>> 3) pace a certain distance out from the building.  Put the barometer on
>> the ground.  Measure the height of the barometer.  Measure the angle 
>between
>> the ground and the line connecting the tops of both.  Use Trig to 
>calculate
>> the height.
>
>Disallowed: you are not given a ruler. If you assume a ruler, why not
>a surveyer's transit, and cut right to the chase?

Oh, come now.  You can get at least a 10% answer using "physical" 
measurements of inches, feet, meters, etc, and use measurements of 
two sides as a substitute for a protractor.  Besides, you can use 
the compass you carried to navigate to the building for angle measurements. 
And, to be precise, you should make all measurements in "barometer" units 
instead of pacing it off -- or measure your pace in barometers.

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. 

>> 5) As above, but swing the barometer in pendulum fashion.
>
>Disallowed: no rope (but very slick; I didn't think of this one)

You can use your belt, especially if you use a rope for a belt that day. 

What went unsaid here is that you use the pendulum period to determine 
the difference in gravity at the top and bottom of the building and 
deduce its height. 

(Not exactly a way to get a 10% answer, but definitely in the spirit of 
the competition.)

Also, you can always get a rope: just make borrowing it part of the deal 
you make with the building superintendent....

--
J. A. Carr                                    |  "The New Frontier of which I  
jac@gw.scri.fsu.edu                           |  speak is not a set of promises
Florida State University  B-186               |  -- it is a set of challenges."
Supercomputer Computations Research Institute |   John F. Kennedy (15 July 60)
Newsgroups: sci.physics
From: N020BA@tamvm1.tamu.edu
Subject: Re: What's new with chaotic dynamics?
Organization: Texas A&M University
Date: Wed, 2 Sep 1992 03:08:46 GMT

    There's only one problem I can see-jumping onto a neighboring trajectory.
A chaotic attractor's trajectories repel each other locally but converge asy-
totically in the region of the phase space called the attractor. How are you
going to switch trajectories if those trajectories repel?
 
========================================================================
The truth may hurt, but lies hurt more.  | My opinions are mine and mine
The difference between left-wing incomp- | alone. I speak for myself and
etance and right-wing incompetance is    | no-one else.
the difference between cat #$!& and dog  |______________________________
#$!&. Reply to N020BA@tamvm1.tamu.edu.        Bill and Opus in '92!!