document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1081529>Question 1081529</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Kirby moves with constant speed 5 units per hour along the line <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+3x%2F4+%2B6 ALIGN=MIDDLE  ALT=\"y+=+3x%2F4+%2B6\"   DISABLED_style= \"max-width:90%; height:auto;\" > crossing<BR>\n" );
document.write( "the y-axis at midnight and the x-axis later. When is the x-axis crossing made? What does it<BR>\n" );
document.write( "mean to say that Kirby’s position is a function of time? What is Kirby’s position 1.5 hours<BR>\n" );
document.write( "after midnight? What is Kirby’s position t hours after midnight? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #695623 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=695623\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Kirby moves with constant speed 5 units per hour along the line <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y+=+3x%2F4+%2B6 ALIGN=MIDDLE  ALT=\"y+=+3x%2F4+%2B6\"   DISABLED_style= \"max-width:90%; height:auto;\" > crossing<BR>\n" );
document.write( "the y-axis at midnight and the x-axis later. When is the x-axis crossing made?<BR>\n" );
document.write( "The x-axis is crossed when y=0.<BR>\n" );
document.write( "y = 3x/4 +6 = 0<BR>\n" );
document.write( "3x = -24<BR>\n" );
document.write( "x = -8<BR>\n" );
document.write( "The distance from (-8,0) to (0,6) = 10 units.<BR>\n" );
document.write( "10/5 = 2 hours --> x-axis crossed at 0200.<BR>\n" );
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document.write( "What does it mean to say that Kirby’s position is a function of time?<BR>\n" );
document.write( "It varies with time.<BR>\n" );
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document.write( "What is Kirby’s position 1.5 hours after midnight?<BR>\n" );
document.write( "He's 7.5 units from (0,6) on the line, and 2.5 units from (-8,0)<BR>\n" );
document.write( "--> (-6,1.5)<BR>\n" );
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document.write( "What is Kirby’s position t hours after midnight?<BR>\n" );
document.write( "Since he's moving right to left (on the graph):<BR>\n" );
document.write( "x(t) = -t<BR>\n" );
document.write( "y(t) = -3t/4 + 6 </SPAN>\n" );
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