document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1154333>Question 1154333</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A toy rocket is shot vertically into the air from a launching pad 9 feet above the ground with an initial velocity of 80 feet per second. The height h, in feet, of the rocket above the ground at t seconds after launch is given by the function h(t)=-16t^2+80t+9. How long will it take the rocket to reach its maximum height? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #776730 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=776730\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> h(t) = -16t^2 + 80t + 9.\r<BR>\n" );
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document.write( "compare with equation <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ax%5E2%2Bbx%2Bc=0 ALIGN=MIDDLE  ALT=\"ax%5E2%2Bbx%2Bc=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "a=-16, b=80 c =9\r<BR>\n" );
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document.write( "time to go to height h  = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-b%2F2a ALIGN=MIDDLE  ALT=\"-b%2F2a\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "=(80/32)= 2.5 s\r<BR>\n" );
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document.write( "time to go maximum height  is  t =  =  =  = 2.5 seconds.\r<BR>\n" );
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document.write( "The maximum height you can get  by substituting this value  t= 3.5 in the formula <BR>\n" );
document.write( "h(t) = -16t^2 + 80t + 9\r<BR>\n" );
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document.write( "h(2.5) = -16*2.5^2 + 80*2.5 + 9.\r<BR>\n" );
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document.write( "h =109m<BR>\n" );
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