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Topic: Straight line on a coin (Read 367 times) |
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BNC
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Straight line on a coin
« on: Sep 9th, 2003, 5:14am » |
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A straight line is drawn on a coin (assume it’s made of homogeneous material). Now, the coin is heated.
What will the drawn line look like now?
1. curved “inside”
2. remain straight
3. curved “outside”
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| « Last Edit: Sep 9th, 2003, 5:15am by BNC » |
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How about supercalifragilisticexpialidociouspuzzler [Towr, 2007]
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TenaliRaman
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Re: Straight line on a coin
« Reply #1 on: Sep 9th, 2003, 5:38am » |
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::remains straight::
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James Fingas
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Re: Straight line on a coin
« Reply #2 on: Sep 9th, 2003, 8:06am » |
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Depends on the metals used in the coin. Most coins have multiple layers. If the edges of the coin are covered, then the line would bend in or out very slightly (depending on whether the subtrate or the coating expands more). If the edges are not covered and there's no picture on the coin, the line should be straight, but the coin could concievably dish, making the line straight only when you look down at it. A picture will only complicate things...
And this assumes that the metal does not have any residual stresses in it that could show up when heated.
[edit]okay, I feel stupid now for not reading the question.[/edit]
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| « Last Edit: Sep 9th, 2003, 12:06pm by James Fingas » |
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Sameer
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Re: Straight line on a coin
« Reply #3 on: Sep 9th, 2003, 10:52am » |
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the question says it is homogenous... so the answer is a straight line..
but yea i do agree with James with the fact that non-homogenous materials may cause bend...
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Sir Col
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Re: Straight line on a coin
« Reply #4 on: Sep 9th, 2003, 11:17am » |
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Would it not depend which part of the coin was heated and where, on the coin, the line was drawn?
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aero_guy
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Re: Straight line on a coin
« Reply #5 on: Sep 9th, 2003, 11:44am » |
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True, it depends on when you measure, as the coin will not heat perfectly evenly, so during the act of changing temp the line will probably curve. Once the new temp has equalized, though, it will be straight again.
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