document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1006685>Question 1006685</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A baseball is hit from a height of 0.8 m. After \"t\" seconds, its height \"h\", in metres, is given by the equation h=&#8722;5t2+20t+0.8. How long does the ball stay at least 15 m above the ground? (5 marks) </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #622810 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=622810\">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+=+-5t%5E2+%2B+20t+%2B+.8+ ALIGN=MIDDLE  ALT=\"+h%28t%29+=+-5t%5E2+%2B+20t+%2B+.8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "I want to solve for <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+%3E=+15+ ALIGN=MIDDLE  ALT=\"+h%28t%29+%3E=+15+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+15+=+-5t%5E2+%2B+20t+%2B+.8+ ALIGN=MIDDLE  ALT=\"+15+=+-5t%5E2+%2B+20t+%2B+.8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-5t%5E2+%2B+20t+-+14.2+=+0+ ALIGN=MIDDLE  ALT=\"+-5t%5E2+%2B+20t+-+14.2+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "use quadratic formula<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+=+-5+ ALIGN=MIDDLE  ALT=\"+a+=+-5+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+20+ ALIGN=MIDDLE  ALT=\"+b+=+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+-14.2+ ALIGN=MIDDLE  ALT=\"+c+=+-14.2+\"   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+-20+%2B-+sqrt%28+20%5E2+-+4%2A%28-5%29%2A%28-14.2%29+%29%29+%2F+%282%2A%28-5%29%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-20+%2B-+sqrt%28+20%5E2+-+4%2A%28-5%29%2A%28-14.2%29+%29%29+%2F+%282%2A%28-5%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=+t+=+%28+-20+%2B-+sqrt%28+400+-+284+%29%29+%2F+%28-10+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-20+%2B-+sqrt%28+400+-+284+%29%29+%2F+%28-10+%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+-20+%2B-+sqrt%28+116+%29%29+%2F+%28-10+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-20+%2B-+sqrt%28+116+%29%29+%2F+%28-10+%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+-20+%2B+10.7703+%29+%2F+%28-10%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-20+%2B+10.7703+%29+%2F+%28-10%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+=+9.2297+%2F+10+ ALIGN=MIDDLE  ALT=\"+t+=+9.2297+%2F+10+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+.923+ ALIGN=MIDDLE  ALT=\"+t+=+.923+\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "and, also<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+-20+-+10.7703+%29+%2F+%28-10%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-20+-+10.7703+%29+%2F+%28-10%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+=+30.7703%2F10+ ALIGN=MIDDLE  ALT=\"+t+=+30.7703%2F10+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+3.077+ ALIGN=MIDDLE  ALT=\"+t+=+3.077+\"   DISABLED_style= \"max-width:90%; height:auto;\" > sec<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "The difference in these times is the time period<BR>\n" );
document.write( "when <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+h%28t%29+%3E=+15+ ALIGN=MIDDLE  ALT=\"+h%28t%29+%3E=+15+\"   DISABLED_style= \"max-width:90%; height:auto;\" > m<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+3.077+-+.923+=+2.154+ ALIGN=MIDDLE  ALT=\"+3.077+-+.923+=+2.154+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "2.154 sec answer<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "Here's a plot of the equation:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+400%2C+400%2C+-1%2C+5%2C+-3%2C+25%2C+15%2C+-5x%5E2+%2B+20x+%2B+.8+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+400%2C+400%2C+-1%2C+5%2C+-3%2C+25%2C+15%2C+-5x%5E2+%2B+20x+%2B+.8+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );