document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=864627>Question 864627</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A model rocket is launched from the roof of a building. Its flight path is modeled by h equals minus 5 t squared plus 30 t plus 10 where h  is the height of the rocket above the ground in meters and t is the time after the launch in seconds. \r<BR>\n" );
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document.write( "What is the rocket's maximum height?<BR>\n" );
document.write( "How long before the rocket reaches the ground? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #521187 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=521187\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A model rocket is launched from the roof of a building. Its flight path is modeled by h equals minus 5 t squared plus 30 t plus 10 where h is the height of the rocket above the ground in meters and t is the time after the launch in seconds. <BR>\n" );
document.write( "What is the rocket's maximum height?<BR>\n" );
document.write( "How long before the rocket reaches the ground?<BR>\n" );
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document.write( "h=-5t^2+30t+10<BR>\n" );
document.write( "complete the square:<BR>\n" );
document.write( "h=-5(t-6+9)+45+10<BR>\n" );
document.write( "h=-5(t-3)^2+55<BR>\n" );
document.write( "This is an equation of a parabola that opens down with vertex at (3,55)<BR>\n" );
document.write( "maximum height=55m<BR>\n" );
document.write( "..<BR>\n" );
document.write( "when rocket reaches the ground, h=0<BR>\n" );
document.write( "-5t^2+30t+10=0<BR>\n" );
document.write( "5t^2-30t-10=0<BR>\n" );
document.write( "solve by 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( "a=5, b=-30, c=-10<BR>\n" );
document.write( "ans: t&#8776;6.32 sec<BR>\n" );
document.write( "maximum height? 55m<BR>\n" );
document.write( "How long before the rocket reaches the ground? 6.32sec\r<BR>\n" );
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document.write( " </SPAN>\n" );
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