It's observable and more importantly predictable. That's basically the extent of the science there (don't get me wrong, it's very important and useful, but not the same as true understanding, as you say.)
That's a pretty weak question. Perhaps the OP isn't as strong as you are at physics.
;)
or hooking it up to an ultra-capacitor/battery for regenerative breaking. ;)
I believe intentional shorts are called shunts.
But, you can take an unmagnetized iron rod, orient it correctly in the earth's field (I ferget which way.) and pound it on one end with a hammer. That will weakly magnetize it.
Jeff
George E. Cawthon wrote Electro-magnetism is one force, another is gravity. Here is your question, name two other natural forces!
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You appear to be the smartest person here. Could you get us started by enumerating the "unnatural forces" before we start listing the "natural forces"?
Obviously you are too bright and too smug to make a 9th grader's mistake of referring to the
4 fundemental forces as "natural forces."All forces are natural. But it is commonly believe (thanks to Uncle Albert) that all forces are derived from 4 fundemental forces. Proving it was one of Einsteins great unfinished works.
Electro-magnetism is one force, another is gravity. Here is your question, name two other natural forces!
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Some, but not all, forces:
Friction, electrostatic, buoyancy, elasticity, adhesive, aerodynamic lift, thrust.
Fictitious forces: coriolis, centrifigual.
Political forces: GOP, DNC.
Gideon wrote: ...
The timing here isn't right--at the time Einstein did special and general relativity, the strong and weak nuclear forces weren't yet identified. In his latter years, his attempts at unification were hindered greatly by being still too early and his unwillingness to accept quantum mechanics as being an actual description of "how the world works". The problem is that without QM, we have no way to describe the miniscule although the large is handled nicely. Unfortunately, even at the large scales, when one gets to the boundary conditions where gravitational fields become immense, then there QM rears its ugly head again.
For readable accounts for any interested, Hawking's "A Brief History of Time" and Brian Greene's various works are recommended. Hawking primarily for up to the time at which the transition to string theories (mid-80s or thereabouts) essentially replacing earlier attempts (such as "supergravity") and Greene for newer developments.
"dpb" wrote in news:1160423336.308758.6200 @i42g2000cwa.googlegroups.com:
Didn't know string theory was that old! Don't get much exposure to that line of stuff any more. Limited to catching something by chance on PBS/Nova/Disc. Sometimes even Cops gets old :-)
How about the strong and weak nuclear forces?
As it turns out, these are implemented via any or any combination of the
4 known fundamental forces of the universe. None of these use either the strong or weak nuclear force. Basically it's the electromagnetic one - via electrostatic repulsion of electron shells of atoms, and any electrostatic attraction between molecule regions having an "above-normal concentration of electron presence" (molecule regions negatively charged) and molecule regions having a "below-normal concentration of electron presence" (molecule regions positively charged). Although often enough we experience gravity.How we feel these (or the non-fictitious forces that the fictitious ones are "the equal and opposite reaction to", as in the force that forces an object to take a curved path) is normally through the electromagnetic one of the four known fundamental forces of the universe.
- Don Klipstein ( snipped-for-privacy@misty.com)
I think you are the second with that statement. Must be because neither of you can answer it.
Guess you missed the fact that the kids question was based on a fallacy. People that know practically nothing about science, e.g. most 9 year old children, often ask questions based on a fallacy.
Ha. Ha. I didn't expect an answer, it was just a tease since the kid's question is about basic physics. It does bite my butt that few adults can answer two simple question, Name three natural forces and name three states of matter. (Don't expect anyone to list all the forces and all the recognized states of matter). That very basic information about the world we live in isn't taught in schools or at least it isn't taught in a manner that students retain or understand it.
Being snotty and a jackass makes you smarter?
9th graders don't generally know anything about forces and in most school have not take chemistry or physics. But you may have me there, fundamental is a better words than natural.Wow! I always thought learning basic information was more valuable that learning who discovered it and when it was discovered.
Uh oh. Dangerous to raise your head here, prepare to be pounded down. Can't have anyone above the average level.
Don't think dpb has anything to worry about -- it's not being well- educated that sets people off here, it's being a pompous jackass about it. dpb provided information in a polite manner, rather than supercilious questions, quite a different approach to social interaction.
A significant fraction of the people in the country can't reliably identify the atlantic ocean on an unlabled map, their anniversary, or their own freaking email password. And you're expecting to remember what a "state of matter" is?
Don Klipstein wrote: ...
Of course, at the fundamental level, special relativity shows that it's actually space-time that is curved by the gravitational field and the object takes a straight path... :)
I've heard they've recently created new states, and in a search found more than i though:
Bose-Einstein Condensate Liquid:
well, I learned and retained it in the 70s/80s... but i'll bet many folks in the same class havn't. I can't spell for crap though. Different folks will learn and retain different things given the same stimuli/classes. It's just a matter of what folks find to be important to them. Sadly, a large percentage of those folks find trivia about sports or trite television shows to be more important than states of matter and physical forces.
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This old guy finds it incredible, too. All this stuff was essentially unknown when I was finishing undergraduate work and still considered almost purely conjectural even after had finished graduate degree some ten years later (didn't go straight on, obviously. I'm slow, but not _that_ slow! :) )
If you have any interest at all, I do strongly recommend both Hawking and Greene. Particularly The Brief History of Time is quite short and an easy read (he states in the Foreword that his editors told him his audience could be expected to be halved for every equation he included so there's only one in the entire book! :) ) but does a nice job of explaining the overall transition from the Aristolean thru Copernican and to Newtonian physics, then the "crises" that led to modern physics in a way that is quite coherent. It does cover the very rudimentary ideas of string theories towards the end, but was written when these ideas were still evolving quite rapidly so that to try to do more than mention them would have detracted more than explained.
Greene (The Elegant Universe, etc.) is a little harder going, but still not at all a textbook but a general description/overview and written more recently. The concepts there start to get _really_ esoteric (as if quantum effects and special relativity aren't bizarre enough as compared to "normal" experience! :) ), but are fascinating as to what may (and I emphasize the "may" here) turn out to be the way the universe is actually put together. (There was at least one NOVA built around The Elegant Universe, but I found it difficult to really get much from as the production seemed somehow disjointed. It was interesting, but not satisfying, at least to me. Being able to read the book was better.)
That, of course, was intended to be "general"...
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