Re: FYI data for "realistic" problems

[Ludwik Kowalski <kowalskiL@MAIL.MONTCLAIR.EDU>]

Thanks Aaron, I did not know that I=28 A can possibly be
squeezed out of a new D battery. It means that its internal r is
initially as small as 0.05 ohms. A battery rated for 15 ampere-
hours would be able to supply such current for nearly 30 min,
if r remained constant.

Does anybody know what how quickly r increases as the
function of the charge delivered (ampere-hours)? For example,
can the current be still as large as 10 or 20 A after a charge of
about 10 ampere-hours has been taken out (that is after 2/3 of the
rated ability). I guess a student-oriented "technological research"
project can be formulated to answer questions of that kind.
Ludwik Kowalski

Aaron Titus wrote:

> FYI
>
> When I write homework problems for my physics class, I try to choose
> somewhat realistic situations with realistic data.  For instance, if I'm
> giving a Newton's second law problem where students analyze the forces on a
> tennis ball, I try to give the mass of an actual tennis ball.  A useful
> site for finding some of this data is at
>
> http://hypertextbook.com/facts/index-topics.shtml