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Tie a rope around the Earth's equator. Now untie it, and

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Thread replies: 23
Thread images: 4

Tie a rope around the Earth's equator. Now untie it, and add one meter of rope. Tie again. How loose will it be? In other words: what will be the distance between the ground and this rope going around the Earth? Most people will either answer "close to 0" or (a few) "one meter". Do the math, and the answer may surprise you.

^mind was blown
>>
>>8335536
I think you stated the problem backwards, because the actual answer is 1/2pi meters which is pretty close to 0 compared to 1 meter. My mind was not blown.
>>
>>8335536
D=C/pi
D2-D1 = C2/pi - C1/pi = (C2-C1)/pi = (C1+1+C2)/pi) = 1/pi = ~0.24

so about 12cm?
Not sure what the point of this was, unless it's your homework.
>>
less than 1mm
>>
It will still be on the ground because the mass of the rope falling into depressions as it goes over land will pull it taught.
>>
Ce= re*2pi; (Ce + 1)/2pi = r1; (re*2pi + 1)/2pi = r1; re - (re*2pi + 1)/2pi = d; re - re + 1/2pi =d; d =1/(2pi) = 0.16 m
>>
>1/pi = ~0.24
>>
File: radius.jpg (18KB, 362x138px) Image search: [Google]
radius.jpg
18KB, 362x138px
Almost 16 cm
>>
File: radius2.jpg (16KB, 363x141px) Image search: [Google]
radius2.jpg
16KB, 363x141px
>>8335604
Funny thing tho, it doesn't matter
if you do the wrap around a tennis ball
or the world, the numbers are the same:
a 15.92 cm increase of radius will result in the
rope lengthening by 1 m.
>>
File: peak.png (3KB, 229x306px) Image search: [Google]
peak.png
3KB, 229x306px
>>8335536
I did this in primary school when we learned bout circles for the first time.

A more interesting one I calculated was
>Tie a rope around the Earth's equator. Now untie it, and add one meter of rope. Tie again. pull the rope to a peak as in the pic, how high is the peak?
>>
>>8335536
about one dick
>>
>>8335633
Thats very cool
>>
>>8335633
obviously
>2pi(r+dr) = 2pir + 2pidr
WOW SO AMAZING!
>>
>>8335727
The farthest I can get is:
1=2r*acos(r/(r+h))+2sqrt(2r^2+rh+h^2)
How do you solve an equation like that?
>>
>>8335756
>pidr
cyka blyat
>>
>>8335763
Russians, Russians everywhere
>>
>>8335762
Alright I actually messed up that equation a bit. There should be no r^2 term inside the radical. And I figured that the angle would be small enough to use paraxial approximation, so the acos term is also 0. I get a height of approximately 39 mm, amazing.
>>
c=2r π
Δc=1
Δr=1/(2π)=0.1592
>>
op pic looks like boobies tee hee
>>
>>8335536
The answer is -1/12
>>
>>8335536
looks like boobs
>>
literraly this u fagot

>http://www.qbyte.org/puzzles/p004s.html
>>
>>8335536
Assuming the earth is a perfect sphere (it isn't)
the answer would be:
(22/7d + 22/7) - 22/7d
measure diameter in meters and provide answer in meters, this is the distance between the proportionately stretched out rope and the fictional perfect circumference of the earths entirely smooth equator.
Thread posts: 23
Thread images: 4


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