Is there a simple equation to figure out the following?: We have a 0.3
mm thick (non-elastic) fabric, it's 1500m long and we want to roll it
up into a roll on a 20 inch spindle. what is the diameter of the roll
going to be? thanks!

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Request for Question Clarification by palitoy-ga on 06 Feb 2006 12:27 PST

Hello janomat-ga,

Thank-you for your question.

Would this online calculator be sufficient for an answer?

http://www.oliner.com/Vulcanex/rollcalc.htm

palitoy-ga

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Clarification of Question by janomat-ga on 06 Feb 2006 13:18 PST

yes, that'll do. perfect!

janomat...

Since your question asked if there were a formula to determine
the outside diameter of the roll, it seemed to me that providing
you with the formula might be more satisfactory than simply 
giving you the answer, so I had a look at the source code for
the online calculator provided by my colleague palitoy-ga, and
was able to translate it for you:

The source code was:
outside = Math.sqrt(((48 * length * thickness)/Math.PI)
 + Math.pow(inside,2))

Translation:

outside diameter -in inches- = the square root of:
{[(48 x length -in feet- x thickness -in inches-)/pi] + [inside
diameter -in inches- squared]}

length = 1500 meters = 4921.25984 feet
thickness = .3 millimeters = .0118110236 inches
inside diameter = 20 inches


So, the square root of:

{[(48 x 4921.25984 x .0118110236)/pi] + [20^2]} =

{[(2790.005573374666752)/3.14159] + 400} =

888.0871066481198221282853586878 + 400 = 

1288.0871066481198221282853586878

The square root of which is 35.889930435264426994886364385512

or 35.89 inches.


Please do not rate this answer until you are satisfied that  
the answer cannot be improved upon by way of a dialog  
established through the "Request for Clarification" process. 
 
A user's guide on this topic is on skermit-ga's site, here: 
http://www.christopherwu.net/google_answers/answer_guide.html#how_clarify 
 
sublime1-ga


Searches done, via Google:

1500 meters in feet
://www.google.com/search?q=1500+meters+in+feet

.3mm in inches
://www.google.com/search?q=.3mm+in+inches

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Request for Answer Clarification by janomat-ga on 06 Feb 2006 13:25 PST

sublime1-ga, thank you for that; my only question is, when i punch in
the numbers into the online calculator, it spits out 96.09 inches as
the outside diameter, and not 35.89 inches... what am i doing wrong?

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Request for Answer Clarification by janomat-ga on 06 Feb 2006 13:28 PST

sublime1! just found out that i had skipped a zero. 35.89 inches it is - so sorry!

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Clarification of Answer by sublime1-ga on 06 Feb 2006 13:50 PST

No problemo!...  : )