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Darren New wrote:
> Actually, I've never seen anyone get the answer write to "why are
> manholes round." I almost hope they ask me that at my next job
> interview, because the interviewer probably doesn't know either. ;-)
I like the fake Feynman answer:
START
Interviewer: Now comes the part of the interview where we ask a question
to test your creative thinking ability. Don't think too hard about it,
just apply everyday common sense, and describe your reasoning process.
Here's the question: Why are manhole covers round?
Feynman: They're not. Some manhole covers are square. It's true that
there are SOME round ones, but I've seen square ones, and rectangular ones.
Interviewer: But just considering the round ones, why are they round?
Feynman: If we are just considering the round ones, then they are round
by definition. That statement is a tautology.
Interviewer: I mean, why are there round ones at all? Is there some
particular value to having round ones?
Feynman: Yes. Round covers are used when the hole they are covering up
is also round. It's simplest to cover a round hole with a round cover.
Interviewer: Can you think of a property of round covers that gives them
an advantage over square ones?
Feynman: We have to look at what is under the cover to answer that
question. The hole below the cover is round because a cylinder is the
strongest shape against the compression of the earth around it. Also,
the term "manhole" implies a passage big enough for a man, and a human
being climbing down a ladder is roughly circular in cross-section. So a
cylindrical pipe is the natural shape for manholes. The covers are
simply the shape needed to cover up a cylinder.
Interviewer: Do you believe there is a safety issue? I mean, couldn't
square covers fall into the hole and hurt someone?
Feynman: Not likely. Square covers are sometimes used on prefabricated
vaults where the access passage is also square. The cover is larger than
the passage, and sits on a ledge that supports it along the entire
perimeter. The covers are usually made of solid metal and are very
heavy. Let's assume a two-foot square opening and a ledge width of 1-1/2
inches. In order to get it to fall in, you would have to lift one side
of the cover, then rotate it 30 degrees so that the cover would clear
the ledge, and then tilt the cover up nearly 45 degrees from horizontal
before the center of gravity would shift enough for it to fall in. Yes,
it's possible, but very unlikely. The people authorized to open manhole
covers could easily be trained to do it safely. Applying common
engineering sense, the shape of a manhole cover is entirely determined
by the shape of the opening it is intended to cover.
Interviewer (troubled): Excuse me a moment; I have to discuss something
with my management team. (Leaves room.)
(Interviewer returns after 10 minutes)
Interviewer: We are going to recommend you for immediate hiring into the
marketing department.
END
Taken from:
http://www.sellsbrothers.com/fun/msiview/#Feynman
I have to strongly agree with one point - why do people keep thinking
they are just round? I've seen *many* square shaped ones.
--
Copywight 1991 Elmer Fudd. All wights wesewved
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>>>>>>mue### [at] nawaz org<<<<<<
anl
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