Re: [asa] writing equations - a request

George had given us an excellent example of how are models of the real
world are only approximations, and these approximations are made at
various levels.
My reponse would be that the system is marvelous but two irons would be
useless for ironing!
Don

Randy Isaac wrote:

> Blackbody radiation wouldn't be reflected but would cool the whole
> system? Reflections take energy too.
> Randy
>
> ----- Original Message ----- From: "George Murphy" <gmurphy@raex.com>
> To: "Bill Hamilton" <williamehamiltonjr@yahoo.com>; "ASA list"
> <asa@calvin.edu>; "Janice Matchett" <janmatch@earthlink.net>
> Sent: Thursday, July 20, 2006 3:37 PM
> Subject: Re: [asa] writing equations - a request
>
>
>> With perfect reflectors &c - again this is an ideal
>> Gedankenexperiment - all the rays emitted by the iron should go to
>> the other focus.
>>
>> But ray optics is only an approximation.
>>
>> Shalom
>> George
>> http://web.raex.com/~gmurphy/
>> ----- Original Message ----- From: "Bill Hamilton"
>> <williamehamiltonjr@yahoo.com>
>> To: "George Murphy" <gmurphy@raex.com>; "ASA list" <asa@calvin.edu>;
>> "Janice Matchett" <janmatch@earthlink.net>
>> Sent: Thursday, July 20, 2006 3:09 PM
>> Subject: Re: [asa] writing equations - a request
>>
>>
>>> What about
>>> the heat energy that is disipated from the iron into the clothes
>>> the heat energy that is absorbed by the air between the two irons
>>> the heat energy that is absorbed by objects in the room
>>> (including the
>>> person doing the ironing)
>>> ???
>>>
>>> --- George Murphy <gmurphy@raex.com> wrote:
>>>
>>>> Sort of, but the connection is pretty remote.
>>>>
>>>> The thrifty owners of the laundry have constructed their building
>>>> in the form
>>>> of an ellipsoid, and put irons at both foci. All the radiation
>>>> from an
>>>> instrument at one focus as it irons clothes is reflected to the
>>>> other focus
>>>> (by a well known property of the ellipse) & heats the other iron,
>>>> which can
>>>> then be used to iron other clothes. No heat is lost & no money
>>>> needs to be
>>>> spent in heating the irons once they've been heated up initially.
>>>>
>>>> What's wrong with this picture?
>>>>
>>>> (Of course an iron - whether a "mangle" or the usual household
>>>> variety -
>>>> isn't a mathematical point but that's not the "point" here.)
>>>>
>>>> Shalom
>>>> George
>>>> http://web.raex.com/~gmurphy/
>>>> ----- Original Message ----- From: Janice Matchett
>>>> To: George Murphy ; ASA list
>>>> Sent: Thursday, July 20, 2006 12:17 PM
>>>> Subject: Re: [asa] writing equations - a request
>>>>
>>>>
>>>> At 11:27 AM 7/20/2006, George Murphy wrote:
>>>>
>>>>
>>>> A teaser: How many know "The paradox of the Chinese laundry"?
>>>>
>>>>
>>>> @ Physicists know that we don't live in a frictionless world, so
>>>> does it
>>>> have anything to do with a lack of friction?
>>>>
>>>> ~ Janice
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> Bill Hamilton
>>> William E. Hamilton, Jr., Ph.D.
>>> 248.652.4148 (home) 248.821.8156 (mobile)
>>> "...If God is for us, who is against us?" Rom 8:31
>>>
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>>
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>
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-- 
Donald A. Nield
Associate Professor, Department of Engineering Science
University of Auckland
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