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09-26-2008, 07:14 PM
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| |  An oldie
Here's an oldie you might enjoy . . . or not.
Two 20-foot poles are erected perpendicular to the ground.
The ends of a 30-foot rope is attached to the tops of the poles.
The rope hangs naturally and its lowest point is 5 feet from the ground.
How far apart are the poles? Code: * *
| |
| * * |
| * * |
20 | * | 20
| : |
| :5 |
| : |
--*-------+-------*--
: - - - ? - - - :
NOTE: Ropes, cables, etc. do NOT hang in a parabolic shape.
. . . . . The shape is a catenary.
If you already know the answer, please don't give it away.
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09-26-2008, 11:03 PM
| | Grand Panjandrum | | Join Date: Nov 2005
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Quote:
Originally Posted by Soroban  Here's an oldie you might enjoy . . . or not. Two 20-foot poles are erected perpendicular to the ground. The ends of a 30-foot rope is attached to the tops of the poles. The rope hangs naturally and its lowest point is 5 feet from the ground. How far apart are the poles? Code: * *
| |
| * * |
| * * |
20 | * | 20
| : |
| :5 |
| : |
--*-------+-------*--
: - - - ? - - - :
NOTE: Ropes, cables, etc. do NOT hang in a parabolic shape. . . . . . The shape is a catenary.
If you already know the answer, please don't give it away.
. | Well I didn't know the answer but it took only ~5 seconds to deduce it.
RonL |
09-27-2008, 05:04 AM
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Got it in two seconds before I've even finished reading the ques  However, I wonder if the diameter of the poles should be taken into consideration :P
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09-27-2008, 06:07 PM
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I think, in white -> 0 |
09-27-2008, 07:39 PM
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I didn't get it after about 4 minutes and I gave up! I leave a comment in white : I was thinking on the sketch... that is probably why I didn't get it. I could have sketch it on a sheet though. Nice one!
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11-21-2008, 08:32 AM
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| | Re :
So what is the correct answer ? |
12-02-2008, 08:50 AM
|  | meh... | | Join Date: Feb 2007 Location: New York, USA
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Quote:
Originally Posted by mathaddict So what is the correct answer ? | i believe Obsidantion has the right answer (post #4)
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12-12-2008, 01:49 AM
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| | Re :
gotk it , the diagram brings confucion . haha , nice oldie |
12-13-2008, 03:23 PM
| | meh... | | Join Date: Feb 2007 Location: New York, USA
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Quote:
Originally Posted by mathaddict gotk it , the diagram brings confucion . haha , nice oldie | i agree. haha, i've tricked a lot of students with this since i saw it, because they all try to use the diagram to figure stuff out. and that whole explanation about catenaries (which i extended, of course) doesn't make things any easier.
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12-14-2008, 09:37 AM
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Quote:
Originally Posted by Soroban Here's an oldie you might enjoy . . . or not.
Two 20-foot poles are erected perpendicular to the ground.
The ends of a 30-foot rope is attached to the tops of the poles.
The rope hangs naturally and its lowest point is 5 feet from the ground.
How far apart are the poles? Code: * *
| |
| * * |
| * * |
20 | * | 20
| : |
| :5 |
| : |
--*-------+-------*--
: - - - ? - - - :
NOTE: Ropes, cables, etc. do NOT hang in a parabolic shape.
. . . . . The shape is a catenary.
If you already know the answer, please don't give it away.
. | Yeah, I got it, it's a Quadrilateral is formed with the height from string.., I won't tell you what type, that's a clue  | | Thread Tools | | | | Display Modes |  Linear Mode | 
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