document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=71246>Question 71246</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me solve this problem\r<BR>\n" );
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document.write( "An object is projected upward from the top of the tower. it's distance in feet above the ground after t seconds is given by  s(f)=-16t^2 +64t +80. How many seconds will it take to reach ground level?\r<BR>\n" );
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document.write( "I would really like to know how to figure this out.<BR>\n" );
document.write( "Thanks to anyone who is willing to help me </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #50978 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=50978\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> After t seconds, the height of an object with an initial upward velocity of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v%5Bo%5D ALIGN=MIDDLE  ALT=\"v%5Bo%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > feet per second and an initial height of <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5Bo%5D ALIGN=MIDDLE  ALT=\"h%5Bo%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" > feet is given by the function: <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s%28t%29+=+-16t%5E2%2Bv%5Bo%5Dt%2Bh%5Bo%5D ALIGN=MIDDLE  ALT=\"s%28t%29+=+-16t%5E2%2Bv%5Bo%5Dt%2Bh%5Bo%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "In your problem, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=v%5Bo%5D+=+64 ALIGN=MIDDLE  ALT=\"v%5Bo%5D+=+64\"   DISABLED_style= \"max-width:90%; height:auto;\" >ft/sec and <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%5Bo%5D+=+80 ALIGN=MIDDLE  ALT=\"h%5Bo%5D+=+80\"   DISABLED_style= \"max-width:90%; height:auto;\" >ft, so you have:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s%28t%29+=+-16t%5E2%2B64t%2B80 ALIGN=MIDDLE  ALT=\"s%28t%29+=+-16t%5E2%2B64t%2B80\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You want to know at what time, t, will the height, h, be 0, so set the function s(t) = 0 and solve for t.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-16t%5E2%2B64t%2B80+=+0 ALIGN=MIDDLE  ALT=\"-16t%5E2%2B64t%2B80+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > You can simplify this a bit by factoring out -16.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-16%28t%5E2-4t-5%29+=+0 ALIGN=MIDDLE  ALT=\"-16%28t%5E2-4t-5%29+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > so:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5E2-4t-5+=+0 ALIGN=MIDDLE  ALT=\"t%5E2-4t-5+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > You can factor this quadratic equation.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28t%2B1%29%28t-5%29+=+0 ALIGN=MIDDLE  ALT=\"%28t%2B1%29%28t-5%29+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > Apply the zero product principle.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%2B1+=+0 ALIGN=MIDDLE  ALT=\"t%2B1+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > and/or <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t-5+=+0 ALIGN=MIDDLE  ALT=\"t-5+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "If <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%2B1+=+0 ALIGN=MIDDLE  ALT=\"t%2B1+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+-1 ALIGN=MIDDLE  ALT=\"t+=+-1\"   DISABLED_style= \"max-width:90%; height:auto;\" > Discard this solution as the time must be a positive value.<BR>\n" );
document.write( "If <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t-5+=+0 ALIGN=MIDDLE  ALT=\"t-5+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" > then <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+5 ALIGN=MIDDLE  ALT=\"t+=+5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So the object will reach ground-level (h=0) in 5 seconds.<BR>\n" );
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