| Title: | Mathematics at DEC |
| Moderator: | RUSURE::EDP |
| Created: | Mon Feb 03 1986 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 2083 |
| Total number of notes: | 14613 |
Hello,
This is the "Hat overboard" problem:
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In a straight stream are two stationary stakes visible above
the sourface, a mile apart, one directly upstream from the
other. A man is rowing a boat upstream, between the two stakes
making some progress against the current, and consequently
approaching the upstream stake just as he passes it his hat blows
off and goes flating downstream. He rows upstream for ten minutes
more ans then turns and rows downstream. He overtakes his hat
just as they pass the downstream stake.
How fast is the current flowing in the river?
_________________________________________________________________
Enjoy,
Kostas G.
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 814.1 | Hint: its velocity is not relativistic | ZFC::DERAMO | Daniel V. D'Eramo | Fri Jan 08 1988 15:05 | 4 |
spoiler (?)
approximately nine billionths of the speed of light :^)
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| 814.2 | SPOILER | CLT::GILBERT | Builder | Sun Jan 10 1988 15:06 | 7 |
Consider the moving river as the frame of reference. The man's hat goes
into the water, he rows away from it for 10 minutes, then rows back toward
it (and overtakes it in another 10 minutes, we conclude).
The view from the bank shows that the hat (and hence the river current)
moves 1 mile in these 20 minutes; 1 mile / 20 minutes = 3 miles / hour,
and that's how fast the river flows.
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| 814.3 | What, no formfeed? | ZFC::DERAMO | Daniel V. D'Eramo | Sun Jan 10 1988 20:15 | 3 |
Oops. Silly me. I think I forgot to double the ten minutes.
Dan
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