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Topic: Revolving Coin (Read 828 times) |
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ThudnBlunder
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Revolving Coin
« on: Sep 13th, 2003, 2:24am » |
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Two touching identical coins lie on a flat table. Coin A is rolled completely around Coin B (without slipping)
and comes to rest in its original position.
Relative to the table, how many revolutions has Coin A made?
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| « Last Edit: Sep 13th, 2003, 2:26am by ThudnBlunder » |
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TenaliRaman
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Re: Revolving Coin
« Reply #1 on: Sep 13th, 2003, 9:48pm » |
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:: wouldn't the answer be 1 or did i miss something?::
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harpanet
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Re: Revolving Coin
« Reply #2 on: Sep 14th, 2003, 6:11am » |
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::If coin B's edge was uncurled and laid out in a straight line then the answer would indeed be 1, but the edge performs its own 360o revolution, thus adding another revolution to coin A.::
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| « Last Edit: Sep 14th, 2003, 6:13am by harpanet » |
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TenaliRaman
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Re: Revolving Coin
« Reply #3 on: Sep 14th, 2003, 11:46pm » |
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umm wouldn't that be counted as rotations??
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ThudnBlunder
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Re: Revolving Coin
« Reply #4 on: Sep 15th, 2003, 2:32am » |
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Quote:| umm wouldn't that be counted as rotations?? |
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REVOLUTION (rµv”…-l›“sh…n) n.
1.a. Orbital motion about a point, especially as distinguished from axial rotation.
b. A turning or rotational motion about an axis.
c. A single complete cycle of such orbital or axial motion.
ROTATION (r½-t³“sh…n) n.
1.a. The act or process of turning around a center or an axis.
b. A single complete cycle of such motion.
[American Heritage Dictionary]
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TenaliRaman
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Re: Revolving Coin
« Reply #5 on: Sep 15th, 2003, 8:15am » |
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ok my mistake!!
i misunderstood harpanet's statement totally especially this part ::but the edge performs its own 360o revolution, thus adding another revolution to coin A::
Anyways i am clear about it now.
[edit]Thanks T&B for the dictionary quotes!![/edit]
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| « Last Edit: Sep 15th, 2003, 8:17am by TenaliRaman » |
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ThudnBlunder
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Re: Revolving Coin
« Reply #6 on: Sep 15th, 2003, 8:41am » |
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You are welcome, TenaliRaman.
Check out http://mathworld.wolfram.com/CoinParadox.html
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harpanet
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Re: Revolving Coin
« Reply #7 on: Sep 15th, 2003, 1:33pm » |
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on Sep 15th, 2003, 8:15am, TenaliRaman wrote:...i misunderstood harpanet's statement totally...
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It's not the first time that my descriptions have left something to be desired  . Fortunately my coding is much more precise 
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TenaliRaman
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Re: Revolving Coin
« Reply #8 on: Sep 15th, 2003, 10:59pm » |
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Thanks for the link T&B.
@harpanet -- i am sure abt your precise coding 
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Sir Col
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Re: Revolving Coin
« Reply #9 on: Sep 16th, 2003, 8:37am » |
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on Sep 15th, 2003, 1:33pm, harpanet wrote:| Fortunately my coding is much more precise |
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About that there is little doubt – Euler sends his regards! 
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