What keeps electrons spinning around their nucleus?
in [Relativity]
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From: PD on 28 Mar 2005 08:38 Nick wrote: > What is the velocity of an electron in a shell? > Can they move at different speeds and remain in the > same shell? > > More imporatant is what sustains them in their perpetual motions? A force is not required to keep something in motion. A force is required to *change* an object's motion. What gave you the idea that something moving required something to maintain that motion? PD
From: PD on 28 Mar 2005 08:46 TomGee wrote: > Nick and Mitch, I find it incredible that these posters, all the way > down to "Ghost", cannot remember that the negatively charged electrons > in an atom are attracted to the positively charged protons in the > atom's nucleus and that it is this force of attraction which binds > the electrons to the atom. > > TomGee Electrostatic attraction between the proton and the electron is no more responsible for the sustained motion of the electron than gravity is responsible for the sustained motion of the Moon. Please refer to Newton's first and second laws, which point out that, even classically, no force is required for an object to persist in its motion. A (net) force results in a *change* in motion. If I throw a baseball toward home plate, after the ball leaves my hand what force maintains the horizontal velocity of the ball? Common (high school) student errors: 1. The ball *does* eventually stop horizontally, and then it falls vertically. 2. Gravity converts the horizontal velocity into vertical velocity. 3. The ball *does* slow down horizontally; otherwise it would never fall to the ground. PD
From: TomGee on 28 Mar 2005 12:21 PD, didja ever learn anything in school? 3rd grade Physics: Centrifugal force. Don't ask me to explain that to you. Go to class and ask your teacher. TomGee
From: Sam Wormley on 28 Mar 2005 12:31 TomGee wrote: > 3rd grade Physics: Centrifugal force. > > Don't ask me to explain that to you. Go to class and ask your teacher. > > TomGee > Centrifugal force is a fictitious force because it is a by-product of measuring... http://scienceworld.wolfram.com/physics/CentrifugalForce.html
From: PD on 28 Mar 2005 12:33
TomGee wrote: > PD, > > didja ever learn anything in school? > > 3rd grade Physics: Centrifugal force. > > Don't ask me to explain that to you. Go to class and ask your teacher. > > TomGee Tom, you can either keep babbling nonsense or you can start asking honest questions. A few things: 1. The force *inward* in central motion is called centripetal force, not centrifugal force. The electrostatic attraction between electron and proton is an example of a centripetal force. 2. There is no such thing as centrifugal force, strictly speaking. It is a misleading term for a "false force" that has no true agent to provide it. If this comes as a shock to you, perhaps it's because you're relying on the physics you learned in the 3rd grade. 3. In circular motion, you'll note that the velocity is tangent to the circular trajectory, perpendicular to the radius of the circle. Both the true, centripetal force and the false, centrifugal "force" are along the radius of the circle, perpendicular to the velocity. There is no way that a force that is perpendicular to the velocity can change the magnitude of the velocity, nor does it help in any way to maintain the velocity. 4. Newton's 1st law should also have been taught to you in 3rd grade physics, and you should be reminded that, even in the absence of forces, objects in motion tend to stay in motion. Now, if you find any of this to be intuitively wrong, then your problem is not with special relativity, it's with 3rd grade physics. If you would like corroboration that any of the above is true or false, then simply itemize the thing you think is wrong and ask the newsgroup. PD |