Re: Derivatives

[twayburn@juno.com (Thomas L Wayburn)]

You might describe a model train track that changes from straight to an
arc of a circle suddenly.  I am sure you will get many better responses,
however.  - The Amateur

P.S.   I have read a number of other responses, which I regard as
quibbling.  Obviously, they are not helpful to achieve your goal.  But,
perhaps, you ought to explain that physics is not done in the real world
- rather in a world of ideals that often closely approximates the real
world and always closely enough to be useful.   In the meantime, I would
like to see a really helpful answer to your question!
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On Tue, 28 Oct 1997 22:08:23 -0500 David Abineri <dabineri@dot-net.net>
writes:
> I have always pointed out in my Physics classes that a Displacement vs
> Time graph must always be differentiable if it is to represent a 
> "real"
> situation since one cannot change instantaneously from one velocity to
> another.
>
> Today, the question of the differentiability of the Velocity vs Time
> graph came into question. It seems to me that this may be non
> differentiable, that is to say that acceleration may instantaneously
> change from one value to another. HOWEVER, it is difficult for my high
> school students to come to grips with this at the intuitive level. I
> have shown such graphs to them BUT they seem to be applying their
> knowledge of velocity to acceleration incorrectly. I have also said 
> that
> an object released from rest suddenly goes from zero acceleration to
> 9.8m/s/s but I am not sure I have convinced them yet.
>
> Does anyone know of some nice way(s) of getting this point across? 
>
> Thanks for any help on this one.
>
> David Abineri
>
>
> -- 
> David Abineri     dabineri@dot-net.net