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Topic: [ap-calculus] related rates
Replies: 1   Last Post: Oct 8, 2012 11:38 PM

 Paul A. Foerster Posts: 892 Registered: 12/6/04
Re: [ap-calculus] related rates
Posted: Oct 8, 2012 11:38 PM

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Brett, et al -

The constant volume assumption is a reasonable mathematical model of rate
of change in radius as a function of rate of change in length. It is
perfectly appropriate for AP Calculus students because it allows them to
concentrate on the calculus rather than on properties of real-world
materials.

In the real world, this rate of change is measured by Poisson's ratio,
which may differ from the constant-volume assumption. For a primer on this
phenomenon, do a Google search. Wikipedia has a reasonably good

Regards,
Paul

---------------

"Brett Baltz" <brettbaltz@msdlt.k12.in.us> wrote:

> my class is making their own related rates problems. One group wants to
> compare the rate of change of the length of a bungy cord to its radius
> during a bungy jump. It is reasonable to do this through a constant
> (cylindrical or otherwise) volume, right?
> ---

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