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[Phys-L] Re: notation for initial velocity components



I do it the Tipler way, however I usually write something like F(1 on 2)

BTW, I've shared your "concern" regarding the component subscript and
the nought for initial and usually end up not being very consistant. I
suspect its not a big problem, I can't recall bringing to my attentiona
misunderstanding based on confusion of

V_x__o or V_o__x, I'm warming to the ideas of parenthesis as suggested,
so I may start doing

(V_x)_o
________________________
Joel Rauber
Department of Physics - SDSU

Joel.Rauber@sdstate.edu
605-688-4293



| -----Original Message-----
| From: Forum for Physics Educators
| [mailto:PHYS-L@list1.ucc.nau.edu] On Behalf Of Edmiston, Mike
| Sent: Thursday, October 20, 2005 5:54 PM
| To: PHYS-L@LISTS.NAU.EDU
| Subject: Re: notation for initial velocity components
|
| I'll respond to Carl first, then I have a further complaint
| and/or question about subscripts.
|
| It seems to me students ought to understand parentheses
| fairly well from their math training and from the typical
| algebraic calculator; i.e. do what's in the parentheses
| first. Thus (x-dot)sub-0 seems a good choice to me. Note
| this is also the notation Bob Sciamanda recommended.
|
| Also, I have found that double subscripts are a perpetual problem.
| Below I will use parentheses to contain the subscripted items.
|
| Suppose we have two objects m(1) and m(2) in contact with
| each other, and we are looking at the Newton's 3rd law
| contact forces. We might label these as F(12) and F(21).
| Which is which? Is F(12) the force exerted on m(1) by m(2),
| or is F(12) the force m(1) exerts on m(2).
| Another example would be two charges exerting Coulomb's Law
| forces on each other.
|
| The way I see it, was taught, prefer, is that the subscript
| nearest the primary symbol should describe the primary object
| the force pertains to.
| Therefore, the notation F(12) should describe the force
| experienced by m(1). In my way of thinking, F(12) is the
| force on m(1) because of or caused by or exerted by m(2).
|
| I checked with my copies of Haliday and Resnick, Arfken
| et.al., Fishbane, and a few other older texts on my shelf,
| and they all do it "my way." However, the textbook I am
| currently using (Tipler and Mosca) does it the "backwards
| way." Also Serway (another highly used book) does it
| "backwards" like Tipler does.
|
| Was there a shift in the thinking on this at some point? I
| find this pretty difficult because it's hard to teach an old
| dog new tricks, particularly when the old dog thinks the old
| tricks are still the right ones.
|
|
| Michael D. Edmiston, Ph.D.
| Professor of Chemistry and Physics
| Bluffton University
| Bluffton, OH 45817
| (419)-358-3270
| edmiston@bluffton.edu
|