document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=46551>Question 46551</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the electrical resistance R of a wire varies directly as its length L and inversely as the square of its diameter.  A wire 20 meters long and 0.6 centimeters in diameter made from a certain alloy has a resistance of 36ohms.  What is the resistance of a piece of wire 60 meters long and 1.2 centimenters in diameter made from the same material?\r<BR>\n" );
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document.write( "i know that the equation should look something like this:<BR>\n" );
document.write( "R=k L/D^2\r<BR>\n" );
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document.write( "but from there i get lost when plugging in the values\r<BR>\n" );
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document.write( "36ohms=k (20m)/(.6cm)^2<BR>\n" );
document.write( "if i can figure out K i can plug in the other values and get my answer.<BR>\n" );
document.write( "i figure i have to make m into cm so 20 becomes 2000cm/.36cm if i times by 100<BR>\n" );
document.write( "to get rid of the decimal in denominator i get 3600oms=K* 200000/36<BR>\n" );
document.write( "multiply both sides by 36 and i get 129600oms=200000K<BR>\n" );
document.write( "divide by 200000 <BR>\n" );
document.write( "k=.648<BR>\n" );
document.write( "pluggin in the values that i have from above i get the resistance would be 27ohms. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #30879 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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/cgi-bin/show-face.mpl?user=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=30879\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> R = k*l *(1/(d^2))<BR>\n" );
document.write( "R = resistance of wire<BR>\n" );
document.write( "k = proportionality constant<BR>\n" );
document.write( "l = length of wire<BR>\n" );
document.write( "d = diameter of wire<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36+=+k%2A2000%2A%281%2F%28.6%29%5E2%29 ALIGN=MIDDLE  ALT=\"36+=+k%2A2000%2A%281%2F%28.6%29%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > all values in cm.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36+=+k%2A2000%2F.36 ALIGN=MIDDLE  ALT=\"36+=+k%2A2000%2F.36\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k+=+36%2A.36%2F2000 ALIGN=MIDDLE  ALT=\"k+=+36%2A.36%2F2000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k+=+1296%2F%282%2A10%5E5%29 ALIGN=MIDDLE  ALT=\"k+=+1296%2F%282%2A10%5E5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=k+=+648%2A10%5E%28-5%29 ALIGN=MIDDLE  ALT=\"k+=+648%2A10%5E%28-5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=R+=+k%2Al+%2A%281%2F%28d%5E2%29%29 ALIGN=MIDDLE  ALT=\"R+=+k%2Al+%2A%281%2F%28d%5E2%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=R+=+k%2A6000%2A%281%2F%281.2%29%5E2%29 ALIGN=MIDDLE  ALT=\"R+=+k%2A6000%2A%281%2F%281.2%29%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=R+=+648%2A10%5E%28-5%29%2A6%2A10%5E3%2A%281%2F1.44%29 ALIGN=MIDDLE  ALT=\"R+=+648%2A10%5E%28-5%29%2A6%2A10%5E3%2A%281%2F1.44%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=R+=+6%2A648%2A10%5E%28-2%29%2A.6944 ALIGN=MIDDLE  ALT=\"R+=+6%2A648%2A10%5E%28-2%29%2A.6944\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=R+=+2700%2A10%5E%28-2%29 ALIGN=MIDDLE  ALT=\"R+=+2700%2A10%5E%28-2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=R+=+27 ALIGN=MIDDLE  ALT=\"R+=+27\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "27 ohms is my answer, too<BR>\n" );
document.write( "a quick check<BR>\n" );
document.write( "The 2nd wire is 3 times as long and 4 times the <BR>\n" );
document.write( "cross-section area of the 1st wire<BR>\n" );
document.write( "R2 = 3/4*R1<BR>\n" );
document.write( "R2 = (3/4)* 36<BR>\n" );
document.write( "R2 = 3*9<BR>\n" );
document.write( "R2 = 27 ohms<BR>\n" );
document.write( "OK </SPAN>\n" );
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