- 31 Oct '14 09:44So a new manufacturing process can make graphene in unlimited lengths and you start rolling the stuff up on a 1 cm diameter roller, 1 meter in length and you start rolling up this graphene as it comes off the machine making it. Now we take graphene as being a 1 dimensional object, but it is in fact about 3 angnstroms thick per layer.

So starting with that first layer, how long it is when it reaches 1 meter in diameter? Like a long roll of toilet paper but of course a lot thinner. - 31 Oct '14 19:52 / 2 editsI figured there had to be a pretty simple equation for the generalized problem of calculating the length of a roll based on thickness and diameter.

I was right:

http://www.handymath.com/cgi-bin/rollen.cgi

For this problem,

3 angstroms is 0.0000003 mm

center diameter of 1 cm

outer diameter of 1 m

Calculated Length:

2617732078.6037m

That's 2.6 million km. doesn't actually seem like that much - 01 Nov '14 11:47 / 3 edits

I calculated the first cm on the roll and it came to about 2600 miles but was unsure of how to do the whole thing. I tried to go to your site but get an error message 'server error' or some such, tried three times. I wanted to see what this guy's equation would show for that first cm.*Originally posted by forkedknight***Funny story. That's about the same distance that this guy drove his car:**

http://www.allpar.com/old/high-miles/vaillancourt.php

2.6 million km would wrap around the moon and back three times!

2.6 million km would wrap around the moon and back three times! - 03 Nov '14 00:04 / 1 editHmm, yes, I thought I tried my link before posting, but it doesn't seem to work.

Try

http://www.handymath.com/calculators.html

and select the "Calculator for Rolled Length of Roll of Material" link

The equation itself isn't actually listed, which is slightly frustrating from a curiosity standpoint. - 03 Nov '14 20:37I found another description of an equation to use:

The length of the material will be the product of the number

of layers and the average length of one layer in the roll:

Number of layers = (Do-Di)/(2t) [total thickness/one layer]

Average layer = pi(Do+Di)/2 [circumference at average diameter]

where Do and Di are the outer and inner diameters, and t is the

thickness of the material.

So the length is

L = pi(Do+Di)(Do-Di)/(4t)

= pi/4 (Do^2 - Di^2)/t

I ran that through a calculator, the answer is the same - 04 Nov '14 17:27

As for the first cm, that calculator gets ~262km*Originally posted by sonhouse***I calculated the first cm on the roll and it came to about 2600 miles but was unsure of how to do the whole thing. I tried to go to your site but get an error message 'server error' or some such, tried three times. I wanted to see what this guy's equation would show for that first cm.**

2.6 million km would wrap around the moon and back three times! - 09 Nov '14 18:43 / 1 edit

Yeah, saw that a bit late.*Originally posted by forkedknight***As for the first cm, that calculator gets ~262km**

That guy's Plymouth went through 6 engines but still, he got 278,000 miles out of each one on average. The piece says he changed the oil once a week! That must have been expensive, 52 oil changes per year. Oil must have been cheap in Canada back then.