Re: [Phys-l] [ap-physics] The Swinging Bucket Problem

[Jack Uretsky <jlu@hep.anl.gov>]

Hi all-
	I am not familiar with Paul's use of ``centripetal'' to mean 
''total''.  The use is linquistically correct in the swinging bucket 
problem, but would not be if you replace the bucket by two blocks tied 
together with a string. The inner block would then have both a centripetal 
(string tension force) and a centrifugal string tension force applied to 
it, the algebraic sum of the two forces then summing to a net radial 
force.
	The main point, however, is that the names are inconsequential as 
long as the understanding is clear.
					Regards,
						Jack

On Mon, 24 Sep 2007, Paul Lulai wrote:

> Normal force is that of two surfaces with the force perpendicular to the
> surface.
> Friction is a force btn two surfaces due to their contact
> Gravitational Force is a a force due to masses attraction for each other
> (at the Newtonian level)
> Tension caused by a cable etc..
>
> Centripetal force is the only force I can think of that has a name but
> means total.
> Jack's point that name is 'inconsequential as long as everyone is clear
> on your meaning' is true & well-taken.  I have gone a similar route to
> Dan.  I call it the net radial force.  I try to beat into them that net
> means total and hope that this name works.  I suppose it might also work
> to put similar effort into defining centripetal.  However, it is the 1
> exception to the trend of 'named' forces having a singular cause.
>
> I think I first heard Boris K. use net radial to replace centripetal.  I
> have found it useful with my students.
>
>
> Paul Lulai . . . To wonder is to begin to understand
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