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The following is from "Gravitation and Spacetime", p. 98, by Ohanian, Hans C.
Re: Why a golf bass slices or hooks. Date: 1997/01/23
In article <19970123184401.NAA08589@ladder01.news.aol.com> futthunder@aol.com (FUTTHUNDER) writes:
> Can someone please explain to me why a golf ball slices or hooks? I do > not have an extensive background in physics so it would be helpful to me > to keep the explanation reasonably uncomplicated. Since I am not > experienced in posting on newsgroups (even though I wish I was) it might > be easier for me if you could E-mail your response to Futthunder@aol.com. > Thanks > Allen
Like an electron, a golf ball after being struck has:
when the spin vector does not point with the momentum vector you get some asymmetric aerodynamic effects.
Re: Air Conditioning. Date: 1997/01/23
In article <1997Jan22.021505.22072@lafn.org> aj718@lafn.org (charles meyer) writes:
> Hi there. Can anyone explain the physics or chemistry principles why when > you turn on the air conditioning at the same time the heat is on in the > car when it's raining or cold that it won't fog up the windows? If you > just put the heat on the front windshield becomes all foggy but once you > put the air conditioning on as well it "removes" the fog. TIA. >
Imagine an ice cold glass of water on a hot and humid summer day. The glass gets wet because moisture in the air condenses on the cold surface. I believe in effect the same idea is at work. The air for defogging the window (which i think comes from outside the car and therefore is very damp) is sent through the cold surfaces of the heat absorbing "radiator" of the air conditioning system. This removes moisture from the air. The air i believe is then warmed by the heater and then sent to the window. Remember on cold wet days the windshield is like the cold glass above.
Re: Copenhagen Cosmology (or: Bye-Bye Big Bang). Date: 1997/01/24
In article <5cascu$q0q@geraldo.cc.utexas.edu> candy@mildred.ph.utexas.edu (Jeff Candy) writes: > > I favour Heisenberg's view regarding philosophical difficulties > with regard to QM. The following is taken from his book > > "The Physical Principles of the Quantum Theory" > > ... for visualization, > however, we must content ourselves with two incomplete > analogies -- the wave picture and the corpuscular picture. >
With only the greatest respect for former masters, then be content, and give up the hunt.
Re: Copenhagen Cosmology (or: Bye-Bye Big Bang). Date: 1997/01/27
In article <5ch3am$5bf@geraldo.cc.utexas.edu> candy@mildred.ph.utexas.edu (Jeff Candy) writes: > > ale2@psu.edu: > > |> Sorry this is a bit cryptic. For a minute or two consider the > |> possibility that Heisenberg is wrong about the above: > > |> > |> > ... for visualization, > |> > |> > however, we must content ourselves with two incomplete > |> > |> > analogies -- the wave picture and the corpuscular picture. > > |> Maybe there is a "picture", can you prove no such thing exists? > > The correct picture is a _mathematical_ one. Heisenberg's point > is that no analogy to a classical system (e.g., a baseball or a > water wave) is complete. > I may have read more into the Heisenberg quote. I took it to mean that Heisenberg believed that we could form no image of elementary particles that would imply their quantum nature. I'm sure such a picture exists. Can we agree that this might be possible?
Re: Copenhagen Cosmology (or: Bye-Bye Big Bang). Date: 1997/02/02
In article <5ct27d$hkp@news.fsu.edu> jac@ibms46.scri.fsu.edu (Jim Carr) writes:
> There are enough problems with first-year > courses because of a lack of skill in formal mathematical manipulation > (lots of "concrete thinkers" in the Piaget sense) without adding the > teaching of one-forms in the first weeks. > Some concepts need to be chewed on for a long time before they can be swallowed. New ideas should be introduced as early as possible even if the rigor is not there. Some ideas take years to become comfortable with.
Just my 2 cents.
Re: Common Sense and Science (was Re: TV Asteroid Science). Date: 1997/02/28
In article <5f72sn$9to@hbu005.ha.uk.sbphrd.com> Frank_Hollis-1@sbphrd.com.see-sig (Triple Quadrophenic) writes: > > You get a little bit less than 2 liters. It's quite common when mixing > solvents. You always have to teach fresh graduates that when something > requires 50:50 methanol water (for example) you need to measure equal amount > separately, not pour 500ml water into a measuring cylinder and top it up to > 1L with methanol. > > It's a bit like mixing a liter of golf balls and a liter of baseballs. > they'll fit into less than 2 liters.
All this education and i never learned that! If you made the mix above, 500ml each, how much do you get, about? Thanks for this cool fact.
Re: Common Sense and Science (was Re: TV Asteroid Science). Author: Dave/Kristin Hall <bullardr@ridgecrest.ca.us> Date: 1997/03/07 Forum: rec.arts.sf.science
Triple Quadrophenic (Frank_Hollis-1@sbphrd.com.see-sig) wrote:
: OK, Here goes... : : 100 ml Water + 100 ml MeOH poured into a measuring cylinder.... : : Final volume is about 192 ml.
HEY! What in the heck do you think you're doing? Performing an actual experiment? You're not supposed to do that! This is alt.folklore.science. Land of infinite, yet contradictory "expert opinions." We've no place for hard science here!
Now apologize or we'll tell your mommy.
-- David Hall | Kristin Hall Propulsion Performance Office | no real job as yet... Naval Air Warfare Ctr, Weapons Div | brand new mom... ---------------------------------------------------------------- "Look, you two post funny posts, but, Jesus Christ, have some self respect. This had to be one of the sickest posts I've read on alt.tasteless!" -Damon Chetson
Re: The Aether. Date: 1997/03/06F
In article <5f7el2$mmi@ccshst05.cs.uoguelph.ca> devens@uoguelph.ca (David L Evens) writes:
> ale2 (ale2@psu.edu) wrote: > > : Maybe in some (very) loose way they and the other fundamental fermions > : are the medium. Words, words, words %^( > > To the extent that fermions are their own medium, so are bosons. The > nature of the wavefunctions, however, implies that there is no need for a > medium, because there aren't literal, physical waves to exist in the medium.
I don't share your opinion of what is and what is not.
But as to which is more fundamental,
Fermion fields are the "sources" for all the "fundamental" bose fields. In a sense, without the fundamental fermions there would be no photons, weak bosons, or gluons ( or!? gravitons) . One might be able to show that bose fields are not fundamental but may be thought of as appropriate "mixtures" of fermion fields, if so we could then rightly call the fermion fields more fundamental. Fermions and bosons (now thought of as less fundamental) make up the source term in Einstein's General Relativity. Spacetime owes its existence to the matter fields and "force" fields? The matter fields are spacetime, spacetime is the medium?
Yes, i know, back to the drawing board %^(
Re: 2mm diameter pitot tube. Date: 1997/03/19
In article <332f0e2a.26496095@news.jaring.my> sengkin@pl.jaring.my (Sam) writes: > Greetings. > > Does anyone know how to make a 2mm diameter pitot tube manometer to > measure due to low wind speed (less than 2m/s)? > A very small pressure will build up in the tube. You need to amplify that small pressure into some measurable effect. This can be done (just as it is done with an airplanes airspeed indicator) by connecting the tube to a very large diaphragm (must be much larger than that used in airplane) so that the small pressure difference applied over the large diaphragm will produce a measurable force. The only problem (may be an asset) is that the response time may be long.
If my calculation is right the pressure should be of order 5 N/m^2 or 7E-4 lb/in^2
Re: How much force is 1 Newton? :). Date: 1997/03/21
In article <333219E3.4E77@profence.com> Jay Choi <systems@profence.com> writes:
> And I'm wondering just how much protection that > stuff will really give me is such situations. Also if I were to have a > uniform custom made, how would I go on about testing the material (to > measure exactly 800N resistance, for instance?) Is it as simple as just > putting an equivalent weight on a sword with its broken tip applied to > the fabric and checking at what weight the penetration will occur? Is > 800N indeed enough to provide protection when two 200 lbs fencers are > literally flying toward each other with only the tip of the sword > stopping the action? At what acceleration/velocity would it fail? > > Given the conditions, can we play around with some real numbers here > maybe?
At some point take all the numbers and all the theory and throw it in the waste can.
Do the experiment! But not with another person. Get a 60lb punching bag, the kind boxers use, and strap on the punching bag one of your protective vests. Then get one of your swords and give it a nasty jagged broken end (or what ever is realistic). Now go berserk and see if you can puncture the vest. This should not cost too much and you will get an accurate "feel" for how well you are protected.
Or you might want to take up a safer sport, like hang-gliding %^)
Re: The Alternative Physics and Cosmology FAQ. Date: 1997/04/21
In article <5jgff8$dom$3@enterprise.desy.de> vanesch@jamaica.desy.de (Patrick van Esch) writes: > > When do the quantum pixies get angry and seem to violate > SR ? Whenever we attempt to replace them by a gears-and-levers > kind of explanation.
If gears and levers don't work try something else, maybe square-dancing strings or minimal membranes.
> EVEN if we allow the gears and levers to be hidden. > *then* we run in all sorts of trouble, and we seem to violate SR. > Quantum pixies run the world, and they curse us with inconsistencies > whenever we attempt to see through their plans. > There is a kind of irreducible magic to it and I admit being > fond of it :-)
So am i.
Magic, yes. Irreducible, maybe %^)
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