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# Wired Equator

67 replies to this topic

### #11 larryhl

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Posted 13 June 2007 - 01:46 PM

Well, the way I make it is
C= 40000000M therefore (Cx3.142857143/2=r) the Radius is 62857142.86 M
C= 40000000 + 10 is C = 40000010M therefore the radius is 62857158.57 M
62857142.86 - 62857158.57 is 15.71428571M.

Your answer of 1.6 M would be correct if the wire were only 1 M longer.

Or have I missed it completely?

err...C = 2*pi*r, so r = C/(2*pi). Dunno why you're multiplying by pi, and pi = 3.14159... by the way, not 3.142857...
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### #12 sphinxteroonicat

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Posted 13 June 2007 - 02:40 PM

Well, the way I make it is
C= 40000000M therefore (Cx3.142857143/2=r) the Radius is 62857142.86 M
C= 40000000 + 10 is C = 40000010M therefore the radius is 62857158.57 M
62857142.86 - 62857158.57 is 15.71428571M.

Your answer of 1.6 M would be correct if the wire were only 1 M longer.

Or have I missed it completely?

err...C = 2*pi*r, so r = C/(2*pi). Dunno why you're multiplying by pi, and pi = 3.14159... by the way, not 3.142857...

Yep,

That's how I missed it!
• 0

### #13 domino9

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Posted 19 June 2007 - 08:45 AM

The way I like to think about this is imagine cutting the earth in half (along the equator) and looking at it from above-- it would appear as a circle (well, assuming the earth is perfectly spherical). With the wire being longer than the circumference of the circle, it would make a concentric circle (a circle within a circle). If both the circles shared the same midpoint, (Is that what it's called? It's been too long since I did geometry.) is the distance between the two circles longer than the height of an average human?

So the way you can get the answer is subtracting the radius of the small circle FROM the radius of the big circle, which was what sphinxteroonicat did, and compare that answer to average height of humans (in the right units, of course.)
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### #14 Veracity

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Posted 19 June 2007 - 12:12 PM

Hey, SO like, One time in Band Camp, We did this Math Ditto, right??!!?? lol

You guy are way beyond me here. I thought pie was 1.49 at Denny's

O.k,,, I'll shut up
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### #15 Incognitum

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Posted 22 June 2007 - 10:46 AM

I was just going to suggest anyone being sneaky in Australia would be 'creeping under it'
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### #16 smartmind

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Posted 23 June 2007 - 11:18 AM

All this Math & Algebra is a complete waste of time. Common sense tells us that the earth is not a perfect sphere and hence even if the wire was exactly the same length as the earth's circumference (ie 40,000KM) you could quite comfortably walk under it in many places (or swim under it in the seas/oceans/lakes).

I know because my neighbour's cat is able to get into my garden under a concrete fence base simply by digging through under it!
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### #17 Veracity

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Posted 26 June 2007 - 12:20 PM

All this Math & Algebra is a complete waste of time. Common sense tells us that the earth is not a perfect sphere and hence even if the wire was exactly the same length as the earth's circumference (ie 40,000KM) you could quite comfortably walk under it in many places (or swim under it in the seas/oceans/lakes).

I know because my neighbour's cat is able to get into my garden under a concrete fence base simply by digging through under it!

AGGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH.... Thats all I have to say ,,, AAAGGGHHHHHHHHHHHHHHHHHHHHHHHGHGHGHG....

Why does everyone find it necessary to find the FLAWS in the question? Can you not understand that they are using EARTH as an EXAMPLE for its SIZE...? Rivers, Valleys and Pot hole SHOULD NOT BE FACTORED INTO THIS... Ahhh, forget it. I need to accept the fact that Ignorance is all around us in this world...

Youâ€™re Right, forget the answer... Go look for a river to swim in... LOL
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### #18 dsu

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Posted 28 June 2007 - 10:44 PM

The illusion comes from the notion that 10 meters is infinitesimally small compared to 40,000 km (so the change should be really really small). Yes, so is 1.6 meters compared to 40,000/(2*PI) km
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### #19 Garrek99

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Posted 29 June 2007 - 11:33 AM

The illusion comes from the notion that 10 meters is infinitesimally small compared to 40,000 km (so the change should be really really small). Yes, so is 1.6 meters compared to 40,000/(2*PI) km

Well said dude.
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### #20 Paul

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Posted 29 June 2007 - 09:57 PM

Well, the way I make it is
C= 40000000M therefore (Cx3.142857143/2=r) the Radius is 62857142.86 M
C= 40000000 + 10 is C = 40000010M therefore the radius is 62857158.57 M
62857142.86 - 62857158.57 is 15.71428571M.

Your answer of 1.6 M would be correct if the wire were only 1 M longer.

Or have I missed it completely?

You're about 10 (or Pi squared) times too large.

You multiplied by Pi when you should have divided: Circumference / (2 Pi) = Radius
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