document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=150300>Question 150300</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The force needed to keep a car from skidding on a curve varies jointly as the weight of the car and the square of the car's speed, and inversely as the radius of the curve. If a force of 3600 pounds is needed to keep an 1800 pound car traveling at 20 mph from skidding on a curve of radius 600 feet what force would be required to keep the same car from skidding on a curve of radius 570 feet at 50 mph? Round your answer to the nearest pound of force? \r<BR>\n" );
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document.write( "I don't know the formular for this one and thus don't know how to solve it. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #110274 by </B><A HREF=/tutors/aboutme.mpl?userid=Earlsdon><B>Earlsdon(6294)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Earlsdon><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=110274\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> For problems describing variation of one thing compared to something else, you can derive the formula yourself.<BR>\n" );
document.write( "Here's how:<BR>\n" );
document.write( "Let F = force, W = car's weight, S = car's speed, and R = radius of curvature.<BR>\n" );
document.write( "You can write:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=F+=+kWS%5E2%2FR ALIGN=MIDDLE  ALT=\"F+=+kWS%5E2%2FR\"   DISABLED_style= \"max-width:90%; height:auto;\" > The force, F, varies jointly (and directly) as the the car's weight, W, and the square of the car's speed, S, so W and S go on top and inversely as the radius, R, of the curve, so R goes on the bottom.<BR>\n" );
document.write( "Note that since this is variation problem, it is not correct to say that the force, F, equals the right side, so you must use a constant of variation, and that's the k in the formula.<BR>\n" );
document.write( "Now you can substitute the given numbers for F =(3600 pounds), W = (1800 pounds), and S = (20 mph), and (R = 600 ft.) to find the value of k.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3600+=+k%281800%29%2820%29%5E2%2F600 ALIGN=MIDDLE  ALT=\"3600+=+k%281800%29%2820%29%5E2%2F600\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3600+=+k%281800%29%28400%29%2F600 ALIGN=MIDDLE  ALT=\"3600+=+k%281800%29%28400%29%2F600\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplify.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3600+=+k%281200%29 ALIGN=MIDDLE  ALT=\"3600+=+k%281200%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Divide both sides by 1200.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3+=+k ALIGN=MIDDLE  ALT=\"3+=+k\"   DISABLED_style= \"max-width:90%; height:auto;\" >, so now the formula becomes:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=F+=+3WS%5E2%2FR ALIGN=MIDDLE  ALT=\"F+=+3WS%5E2%2FR\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now substitute the second set of numbers for W = 1800, S = 50mph, and R = 570 ft.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=F+=+3%281800%29%2850%29%5E2%2F570 ALIGN=MIDDLE  ALT=\"F+=+3%281800%29%2850%29%5E2%2F570\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=F+=+3%281800%29%282500%29%2F570 ALIGN=MIDDLE  ALT=\"F+=+3%281800%29%282500%29%2F570\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=F+=+23684 ALIGN=MIDDLE  ALT=\"F+=+23684\"   DISABLED_style= \"max-width:90%; height:auto;\" >pounds of force.<BR>\n" );
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