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 1st October 2012, 02:54 PM #131 Cal Weldon   Speakerholic diyAudio Moderator     Join Date: Jan 2004 Location: Near Vancouver Consider the earth to be spherical with a circumference of 40,000 kms. A string, wrapped around the earth, would measure 40,000 kms. Take another string and raise it 1 cm from the first and go around the earth again. How much longer is the second string? __________________ planet10 needs your help: Let's help Ruth and Dave
 1st October 2012, 04:48 PM #132 PlasticIsGood   diyAudio Member     Join Date: Mar 2012 Location: Bradford 2πcm
terry j
diyAudio Member

Join Date: Aug 2006
Quote:
 Originally Posted by Cal Weldon Consider the earth to be spherical with a circumference of 40,000 kms. A string, wrapped around the earth, would measure 40,000 kms. Take another string and raise it 1 cm from the first and go around the earth again. How much longer is the second string?
Radius of earth is Re. Length of string is 2piRe (or whatever!)

Radius of raised string is (Re + 1cm)

length of that string is 2piRe + 2picm

therefore difference in strings is (2piRe + 2pi cm - 2pi Re)=2pi cm.

Good question, very counterintuitive.

(check my maths tho haha, the reasoning is correct)

Oops, plastic got it first, just realised what looks like an n to me without glasses is prob pi.

PlasticIsGood
diyAudio Member

Join Date: Mar 2012
Quote:
 Originally Posted by terry j Oops, plastic got it first, just realised what looks like an n to me without glasses is prob pi.
It took so long to find on this Windows 7 machine. I was mortified to find the top bar has lost its wiggle. What happened to extended ascii?

It's quite an instructive problem. The relationship between radius and circumference is linear, so simple superposition applies. Counterintuitive perhaps because our conception of the size of a circle is more related to area than to radius or circumference.

 3rd October 2012, 04:24 PM #135 Cal Weldon   Speakerholic diyAudio Moderator     Join Date: Jan 2004 Location: Near Vancouver I think because it's 40,000km, the initial reaction is: It has to be way longer, now let's go find out how much. Hmmm... __________________ planet10 needs your help: Let's help Ruth and Dave
 3rd October 2012, 04:26 PM #136 Cal Weldon   Speakerholic diyAudio Moderator     Join Date: Jan 2004 Location: Near Vancouver Accent codes for Windows: Windows Alt Key Codes Mac: Macintosh Accent Codes __________________ planet10 needs your help: Let's help Ruth and Dave
 3rd October 2012, 04:48 PM #137 Cal Weldon   Speakerholic diyAudio Moderator     Join Date: Jan 2004 Location: Near Vancouver What occurs once in a minute, twice in a moment, but never in a thousand years? __________________ planet10 needs your help: Let's help Ruth and Dave
 3rd October 2012, 05:31 PM #138 Wavebourn   Designer & Technologist diyAudio Member     Join Date: Sep 2006 Location: Pleasant Hill, CA "m" __________________ The Devil is not so terrible as his math model is!
 3rd October 2012, 06:16 PM #139 Cal Weldon   Speakerholic diyAudio Moderator     Join Date: Jan 2004 Location: Near Vancouver __________________ planet10 needs your help: Let's help Ruth and Dave
PlasticIsGood
diyAudio Member

Join Date: Mar 2012
Quote:
 Originally Posted by Cal Weldon Accent codes for Windows: Windows Alt Key Codes Mac: Macintosh Accent Codes
Accessories/system tools/character map.

π

That's Palatino. This editor ignores the typeface of imported text, so I changed the font after pasting.

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