document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=12230>Question 12230</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Dear Sir<BR>\n" );
document.write( "I want calculate length of the plastic film winded on 76.5mm- ID (Inner Diameter)and 104.5mm- OD (Outer diameter)of cylinder?\r<BR>\n" );
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document.write( "Thickness of plastic film is 20micron\r<BR>\n" );
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document.write( "Diameter of the roll after winding film is 600mm\r<BR>\n" );
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document.write( "If you have formula to calculate then can you please tell me.\r<BR>\n" );
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document.write( "Thank you \r<BR>\n" );
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document.write( "Best Regards<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #6192 by </B><A HREF=/tutors/aboutme.mpl?userid=kusha><B>kusha(21)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=kusha><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=6192\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ID  = 76.5 thus Inner Radius = 38.25mm<BR>\n" );
document.write( "OD = 104.5 thus Outer Radius = 52.25 mm<BR>\n" );
document.write( "Thus thickness of roll on a side is 52.25 - 38.25 = 14 mm<BR>\n" );
document.write( "Thickness of film is 20 Micron and 1 micron = 1/1000 mm<BR>\n" );
document.write( "therefore thickness is 1/50 mm or 0.02 mm<BR>\n" );
document.write( "Dividing total thickness by thickness of one strip we get 14/(1/50) = 700 rolls<BR>\n" );
document.write( "The radius of 1st layer is (IR + thickness of film)38.25 + 0.02 mm<BR>\n" );
document.write( "The radius of next layer is                        38.25 + 0.04 mm<BR>\n" );
document.write( "The radius of third layer is                       38.25 + 0.06 mm  AND SO ON FOR 70 layers.<BR>\n" );
document.write( "this becomes an Arithematic Progression with first term 38.27mm and common difference ( d) as 0.02 mm<BR>\n" );
document.write( "We have to calculate circumferences of all these layers and add them. The Circumference formula is 2x(22/7)x R<BR>\n" );
document.write( "Therefore sum of circumferences is \r<BR>\n" );
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document.write( "2x(22/7)x 38.25  + 2x(22/7)x 38.27 +       upto 70 terms\r<BR>\n" );
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document.write( "=2x(22/7)x{38.25+38.27 +-----upto 70 terms)<BR>\n" );
document.write( "  =  44/7 x  (70/2)(2x38.25 + (69x0.02)   sum of n terms of AP (n/2){2a+(n-1)d}<BR>\n" );
document.write( "  = 1557.6 mm after solving above expression\r<BR>\n" );
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