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-----Original Message-----_______________________________________________
From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of John
Denker
Sent: Wednesday, January 29, 2014 7:33 AM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] Nice question on buoyance and balance
On 01/29/2014 02:36 AM, Savinainen Antti wrote:
a former studen of mine send me a link to a nice question:
<http://wealthmanagement.com/question/puzzler-odd-balance>.
I usually ask a variation of this question in my class. It is, in my
opinion, a good example of conceptual reasoning which goes well
beyond rote memorization. Probably many of you have seen this
question before but I thought it might be worth sharing.
I put that in the category of problems that are very much easier to
solve in terms of momentum flow, as opposed to force balance.
++ I was able to solve it at a glance, in a fraction of a
second, using the momentum-flow approach.
-- I had to think about it for a while to figure out a
solution based on force-balance.
The connection between force and momentum-flow is spelled out here:
http://www.av8n.com/physics/force-intro.htm
===
Note that a goodly number of the FCI questions are in the same category.
They go from "Huh?" to "Duh!" when translated to momentum-flow
language.
More importantly, a tremendous number of real-world tasks are in the
same category. For example, fluid dynamics is formulated in terms of
the momentum transfer from one parcel to another. I reckon it is
"possible" to formulate it in terms of the force acting at the
boundary between one parcel and another, but that would be sheer masochism.
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