What keeps electrons spinning around their nucleus?
in [Relativity]
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From: Tom Capizzi on 30 Mar 2005 09:37 "TomGee" <lvlus(a)hotmail.com> wrote in message news:1112166575.882402.239550(a)o13g2000cwo.googlegroups.com... > > Tom Capizzi wrote: >> "TomGee" <lvlus(a)hotmail.com> wrote in message >> > SNIP >> >> > Is everyone here so full of knowledge that they think the basics no >> > longer apply? >> > >> >> You don't recognize the basics when you see them. Centripetal force > is >> a legitimate force, centrifugal force is not. >> >> > Wrong, Cap, it is you who doesn't recognize the basics staring you in > the face. Both are legitimate forces; it depends on which frame you > happen to be in. >> >> >> By the way, centripetal >> acceleration is not a force, it is an acceleration caused by > centripetal >> force. >> When the string breaks the orbiting mass follows a straight line away > from >> the center of rotation. It doesn't take a force to "make" the mass > flee the >> center. It does take a force to restrain the mass from departing. >> >> > If you were to remove that force, would the mass just stop moving? If > not, why not? Answer: Law 1. The natural tendency of a moving mass > is to continue moving following a straight path at a constant speed > whenever there are no external forces acting upon it to cause it to > accelerate (or words to that effect). The inertia of a mass works > against any external forces working to accelerate it and that inertia > is called an inertial force. Pure basics! > > Centrifugal force is what causes a mass to flee from a centripetal > force from the viewpoint of a rotating reference frame, which is no > less valid than a non-rotating frame since, under strict definitions > like those you impose on centrifugal force, there is no such thing. > I still disagree. The rotating frame is an accelerated frame. Even a mass under the influence of no forces whatsoever appears to travel in a curved path. You can do physics in such a frame, but it's like trying to solve Rubik's cube with your eyes closed. Physics is unnecessarily complicated by fictitious forces. > TomGee > > > TomGee >> > >
From: Creighton Hogg on 30 Mar 2005 09:39 On Wed, 30 Mar 2005, PD wrote: <> > IMHO, way, way too many students go to college these days. Like a > factor of 10 to 20 too many. I'm interested in hearing more about what you mean by this statement. My own sentiment is that alot of students who come to university just because they want to get a degree in something might be better served in getting a degree at a two year technical college in something that could get them a job right away.
From: robert j. kolker on 30 Mar 2005 10:01 jmfbahciv(a)aol.com wrote: > > The Mass. board of education is now trying to add science > as part of the high school graduation requirement. The > year proposed was 2008 but news broadcasts are now saying > it can't happen until 2010. Listen for the whinging from > teachers' unions. One of them is already running ads that > they can't teach science because there is only 1 microscope/ > 10 students. That's an awfully high ratio even though the > ads want you to think that it's too low. When I went to > high school, I estimate the ration to be 1/100. While the relative scarcity of lab equipment might impact the quality of lab based science instruction there is no shortage of blackboards or overhead viewscreen devices. The theoretical aspects of physics and the associated mathematics can be taught with the material resources currently at hand. On the other hand biology and chemistry does not a substatial laboratory practice component to be taught properly. If one does not dissect the worm or frog one has no sense of the asymmetry of internal structure of complicated organisms. Bob Kolker
From: Gregory L. Hansen on 30 Mar 2005 10:00 In article <slrnd4l3i1.6h5.dubious(a)radioactivex.lebesque-al.net>, Bilge <cranks(a)fghfgigtu.com> wrote: > Tom Capizzi: > > >I have heard that the evidence for glass flowing is not reliable. It doesn't > >happen very quickly, so it originally came from examination of old glass. > >The old glass was found to be thicker at one end. The assumption was > >that it flowed. However, it was later shown to be an artifact of the way > >glass used to made, by spinning large sheets of it. Has anyone else heard > >similar reports? > > Even if true, I'm not sure that it's relevant. Lots of materials >flow under pressure. For example, the copper gaskets used for >conflat flanges, which are sort the ultimate in vacuum seals, depend >upon the copper to cold flow when you tighten the bolts to acheive a >vacuum seal, but no one treats copper as a liquid. I imagine that >anything would flow under its own weight if the piece of material >had the right dimensions, i.e., long, not very wide, thin and then >stood on its short edge. > > Indium seals, commonly used in low temperature applications, must be tightened, and then an hour later tightened again because the metal relaxes. But for some reason nobody seems to call that a liquid. -- "Tell me, Dr. Einstein, at what time does Boston arrive at this train?"
From: Gregory L. Hansen on 30 Mar 2005 10:17
In article <FQy2e.52523$u76.36815(a)trndny08>, Tom Capizzi <etianshrdlu(a)verizon.net> wrote: > >"TomGee" <lvlus(a)hotmail.com> wrote in message >news:1112166575.882402.239550(a)o13g2000cwo.googlegroups.com... >I still disagree. The rotating frame is an accelerated frame. Even a mass >under the influence of no forces whatsoever appears to travel in a curved >path. You can do physics in such a frame, but it's like trying to solve >Rubik's >cube with your eyes closed. Physics is unnecessarily complicated by >fictitious >forces. Unless you're doing the physics of rotating bodies, or physics on a rotating body. Would the artillerist's job be any easier if he used an inertial frame to find his firing solution rather than the accelerated Earth frame and Coriolis forces? -- "Usenet is like a herd of performing elephants with diarrhea -- massive, difficult to redirect, awe-inspiring, entertaining, and a source of mind-boggling amounts of excrement when you least expect it. " -- Gene Spafford, 1992 |