document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=613929>Question 613929</A>: <I><SPAN STYLE=\"word-break: break-all;\">  If a stone is tossed from the top of a 170 meter building, the height of the stone as a function of time is given by h(t) = -9.8t^2 – 10t + 170, where t is in seconds, and height is in meters. After how many seconds will the stone hit the ground? Round to the nearest hundredth’s place; include units in your answer.\r<BR>\n" );
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document.write( "please this is the only problem I need help with. I just don't understand! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #386333 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=386333\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=++h%28t%29+=+-9.8t%5E2+-10t+%2B+170+ ALIGN=MIDDLE  ALT=\"++h%28t%29+=+-9.8t%5E2+-10t+%2B+170+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "I'll plot this because the plot shows exactly what the<BR>\n" );
document.write( "stone is doing at any time after it's thrown.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+400%2C+400%2C+-2%2C+5%2C+-20%2C+250%2C+-9.8x%5E2+-+10x+%2B+170+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+400%2C+400%2C+-2%2C+5%2C+-20%2C+250%2C+-9.8x%5E2+-+10x+%2B+170+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You can see that at <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+0+ ALIGN=MIDDLE  ALT=\"+t+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, the height, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%280%29+ ALIGN=MIDDLE  ALT=\"+h%280%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, is 170.<BR>\n" );
document.write( "What you are being asked is \" How many seconds have passed<BR>\n" );
document.write( "after stone is thrown until the stone hits the ground?\"<BR>\n" );
document.write( "Note that the stone is not thrown straight up and landing at<BR>\n" );
document.write( "the 170 m height of the building. It is landing 170 m below this<BR>\n" );
document.write( "at the ground level.<BR>\n" );
document.write( "At ground level, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+=+0+ ALIGN=MIDDLE  ALT=\"+h%28t%29+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" >, so I can now say<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=++-9.8t%5E2+-+10t+%2B+170+=+0+ ALIGN=MIDDLE  ALT=\"++-9.8t%5E2+-+10t+%2B+170+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Now I can use the quadratic formula to solve for <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"t+=+%28-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+-9.8+ ALIGN=MIDDLE  ALT=\"+a+=+-9.8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-10+ ALIGN=MIDDLE  ALT=\"+b+=+-10+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+170+ ALIGN=MIDDLE  ALT=\"+c+=+170+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28-%28-10%29+%2B-+sqrt%28+%28-10%29%5E2-4%2A%28-9.8%29%2A170+%29%29%2F%282%2A%28-9.8%29%29+ ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+10+%2B-+sqrt%28+100+%2B+6664+%29%29%2F%28+-19.6+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+10+%2B-+sqrt%28+100+%2B+6664+%29%29%2F%28+-19.6+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+10+%2B-+sqrt%28+6764+%29%29%2F%28+-19.6+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+10+%2B-+sqrt%28+6764+%29%29%2F%28+-19.6+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+10+-+82.244%29%2F%28+-19.6+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+10+-+82.244%29%2F%28+-19.6+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28-72.244%29+%2F+%28-19.6%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28-72.244%29+%2F+%28-19.6%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+3.69+ ALIGN=MIDDLE  ALT=\"+t+=+3.69+\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec ( rounded off )<BR>\n" );
document.write( "The stone hits the ground in 3.69 seconds<BR>\n" );
document.write( "Note that I had to use the negative root in the formula<BR>\n" );
document.write( "because that gave me (-)/(-) or positive time. </SPAN>\n" );
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