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Re: Birthday Wish



My avocation is with supporting people on newsgroups who have
the temerity to ask for help with answering engineering problems
which often seem to involve their real world concerns.

It is notoriously these four formulations of which the folks I
attempt to help are often completely innocent.

That's why I question your questioning my real-world relevance.
It's where I live! :-)

Here's a transcription of an ask from the last week or two:

I want to bring up a tank of liquid from 125degF to 140degF using
hot liquid at 190degF. I want to raise its temperature at 4 degrees
a minute. What flow rate should I use?

(This question is ill-posed enough to be 'real-world', don't you think?
Could it be a dairy-farmer has an application for this answer?
Just for fun, try giving an exact formulation assuming no losses. :-)
Brian


At 19:01 4/10/99 +1000, you wrote:
From one Brian to another,
....
algebraic manipulation in a set of formulas that have little
direct relevance to the real world?

...the thermal "equation" you quote ignores much of
the real world, applying as it does to the interchange of
thermal; energy between 2 systems completely isolated from
their surroundings...

Brian McInnes
...
I wish that all high school physics students
could work problems using three equations of constant acceleration,
namely:
v = u + a.t
v^2 = u^2 + 2.a.x
x = u.t + 1/2 a.t^2

AND
that they could work final temperatures of mixes of liquids or
solid and liquid using the relation:

mass1 x specific heat1 x rise in temperature =
mass2 x specific heat2 x fall in temperature

Thanks in advance.
Brian


brian whatcott <inet@intellisys.net>
Altus OK