My Math Forum A glassblower joining a math forum...
 User Name Remember Me? Password

 New Users Post up here and introduce yourself!

 June 7th, 2009, 04:26 AM #1 Newbie   Joined: Jun 2009 Posts: 2 Thanks: 0 A glassblower joining a math forum... I am here for help with some problems that are beyond my rather basic skills. Rest assured, I do have some basics, and I am not completely useless. http://www.talkglass.com/forum/showthread.php?t=20213 Brian
June 7th, 2009, 07:35 AM   #2
Global Moderator

Joined: Nov 2006
From: UTC -5

Posts: 16,046
Thanks: 938

Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms
Re: A glassblower joining a math forum...

Welcome! I'm always glad to see people with different interests joining. I like to watch glass blowing, but I've never tried it myself. (That takes, you know, stuff. )

But you're going to have to remember to spell things out for us, because we're not going to know your field. Taking the question from your example thread:
Quote:
 i can't find the formula for this. can any body help me figure out how much 50x1.8mm tubing would it take to equal 4 inches of 38x4mm?
My best guess is that 38 is the exterior diameter (in mm) and 4 is the thickness of the tubing (also in mm). If that's so, then the volume of the glass in the latter case is
4 inches * (19^2 * pi mm^2 - 15^2 * pi mm^2) = 544pi mm^2 in
I'll leave the units as they are (rather than multiply out the pi and convert to cubic millimeters), since they'll cancel out this way.
The volume in the second case is
x * (25^2 * pi mm^2 - 23.2^2 * pi mm^2) = 86.76pi * x mm^2

Since you want the two to be the same,
544pi mm^2 in = 86.76pi * x mm^2
544 in = 86.76 * x
544 in / 86.76 = x
x = 6.27 inches

But if my assumptions are wrong (maybe 38 is the interior diameter?) then the answer won't be right.

 June 7th, 2009, 07:38 AM #3 Global Moderator     Joined: Nov 2006 From: UTC -5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms Re: A glassblower joining a math forum... Oh, and a quick approximation (good for large, thin tubes) is old length * old diameter * old thickness / new diameter / new thickness ? new length. In this case it would suggest about 6.7 inches. That way you can check your answer -- if the two come out very different, either you made a mistake on one or you're working with very fat tubing.

 Tags forum, glassblower, joining, math

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post mathbalarka New Users 7 June 13th, 2012 05:23 PM LordofthePenguins New Users 2 February 19th, 2012 06:48 PM elim New Users 0 March 9th, 2010 05:45 AM JD3P New Users 1 December 14th, 2009 08:01 AM jamesuminator New Users 3 August 9th, 2008 03:25 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top