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#1 2009-07-29 03:02:42
- soroban
- Member
- Registered: 2007-03-09
- Posts: 452
"Hanging Chain" problem
.
Sorry, bobbym . . . I had a typo!
|
* | *
: | :
:* | *:
: * | * :
: * | * :
10 : *|* : 10
: | :
: |3 :
: | :
--+--------+--------+----
: - - - x - - - :. . . . . . . .
. . . . . . . .
.
Last edited by soroban (2009-07-30 15:29:19)
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#2 2009-07-30 00:35:50
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: "Hanging Chain" problem
Hi soroban;
I'm getting that the distance between the poles is ≈ 5.2882415 ft. When the lowest point is 4 ft. above the ground.
Last edited by bobbym (2009-07-30 12:14:11)
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#3 2009-07-30 08:05:59
- quittyqat
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- Registered: 2009-04-08
- Posts: 1,215
Re: "Hanging Chain" problem
| * | * : | : :* | *: : * | * : : * | * : 10 : *|* : 10 : | : : |4 : : | : --+--------+--------+---- : - - - x - - - :
The illustration says that the hanging rope is 4 feet above the ground at its lowest point, not 3 as you said. 
Last edited by quittyqat (2009-08-08 02:45:13)
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#4 2009-07-30 11:14:13
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: "Hanging Chain" problem
Hi soroban;
There is no solution when it hangs 3 ft. above the ground. Think about it. The line down the center is 7ft. To go down that line and back is 14 ft. You don't have a catenary just a line straight down the center. If you pull the ends apart the length of the chain must get larger than 14 ft. or the lowest point must rise.
Last edited by bobbym (2009-07-30 12:13:29)
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#5 2009-07-30 15:35:16
- soroban
- Member
- Registered: 2007-03-09
- Posts: 452
Re: "Hanging Chain" problem
Hello, bobbym!
Your reasoning is correct: the rope hangs straight down and straight up.
So this means that the poles are 0 feet apart.
It was meant to be a trick question ... with an unexpected answer.
. . (And all that stuff about catenaries was just misdirection.)
But I ruined it with my typo . . . sorry!
.
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#6 2009-07-30 22:03:54
- bobbym
- bumpkin
- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606
Re: "Hanging Chain" problem
Hi soroban;
It's OK. Kept me busy, so thanks.
In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.
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#7 2009-08-07 07:58:19
- wintersolstice
- Real Member
- Registered: 2009-06-06
- Posts: 128
Re: "Hanging Chain" problem
I did try and make a formula for relating the "Depth" "lenght" and width of a "catenery" using the fact that it's
but I hit a snag! I'm not giving up that easy though.PS sorry I just can't find the code for "hyperbolic trig fuctions" or haven't they been added yet? And I'm still struggling with the code
Last edited by wintersolstice (2009-08-07 08:05:39)
Why did the chicken cross the Mobius Band?
To get to the other ...um...!!!
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#8 2009-08-07 10:38:43
- soroban
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- Registered: 2007-03-09
- Posts: 452
Re: "Hanging Chain" problem
I can't find the code for "hyperbolic trig fuctions"
. .
.
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