document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=908390>Question 908390</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A fireworks shell is shot straight up with an initial velocity of 80 feet per second. Its height s after t seconds is given by the equation <BR>\n" );
document.write( "s = 80t &#8722; 16t2.<BR>\n" );
document.write( " If the shell is designed to explode when it reaches its maximum height, how long after being fired, and at what height, will the fireworks appear in the sky?\r<BR>\n" );
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document.write( "time=_______ sec<BR>\n" );
document.write( "height=_________ft </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #551005 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=551005\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A fireworks shell is shot straight up with an initial velocity of 80 feet per second. Its height s after t seconds is given by the equation <BR>\n" );
document.write( "s = 80t &#8722; 16t2.<BR>\n" );
document.write( " If the shell is designed to explode when it reaches its maximum height, how long after being fired, and at what height, will the fireworks appear in the sky?<BR>\n" );
document.write( "Don't burden us with gibberish.<BR>\n" );
document.write( "s = 80t &#8722; 16t2.  What is that?<BR>\n" );
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document.write( "h(t) = 80t - 16t^2<BR>\n" );
document.write( "Use ^ for exponents, Shift 6<BR>\n" );
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document.write( "The max ht is the vertex of the parabola.<BR>\n" );
document.write( "The vertex is at t = -b/2a = 80/32 = 2.5 seconds<BR>\n" );
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document.write( " t = 2.5 seconds<BR>\n" );
document.write( "h(2.5) = 200 - 100 = 100 feet<BR>\n" );
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document.write( "don't waste your time and mine with this<BR>\n" );
document.write( "time=_______ sec<BR>\n" );
document.write( "height=_________ft </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );