document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1009309>Question 1009309</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rocket is shot into the air can be modeled by the equation y= -16x^2 + 420x + 250, where x represents the time the rocket is in the air and y represents the <BR>\n" );
document.write( "height of the rocket at the given time. \r<BR>\n" );
document.write( "\n" );
document.write( "What is the initial height of the object?\r<BR>\n" );
document.write( "\n" );
document.write( "What is the initial velocity of the object?\r<BR>\n" );
document.write( "\n" );
document.write( "At what time does the rocket reach the ground?\r<BR>\n" );
document.write( "\n" );
document.write( "At what time does the rocket reach its maximum height?\r<BR>\n" );
document.write( "\n" );
document.write( "What is the maximum height achieved by the rocket?\r<BR>\n" );
document.write( "\n" );
document.write( "At what time is the rocket at 200ft?\r<BR>\n" );
document.write( "\n" );
document.write( "At what time is the rocket at 1500ft?\r<BR>\n" );
document.write( "\n" );
document.write( "What is the height of the rocket at 3.75 seconds?\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #624827 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=624827\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A rocket is shot into the air can be modeled by the equation y= -16x^2 + 420x + 250, where x represents the time the rocket is in the air and y represents the <BR>\n" );
document.write( "height of the rocket at the given time. <BR>\n" );
document.write( "What is the initial height of the object?:: f(0) = 250 ft.<BR>\n" );
document.write( "------------------------------------------------------- <BR>\n" );
document.write( "What is the initial velocity of the object?:: 420 ft/sec<BR>\n" );
document.write( "------------------------------------------------------------- <BR>\n" );
document.write( "At what time does the rocket reach the ground?<BR>\n" );
document.write( "Solve:: -16x^2 + 420x + 250 = 0<BR>\n" );
document.write( "x = 26.83 seconds<BR>\n" );
document.write( "------------------------------- <BR>\n" );
document.write( "At what time does the rocket reach its maximum height?<BR>\n" );
document.write( "Ans:: when x = -b/(2a) = -420/(-2*-16) = 13.125 sec<BR>\n" );
document.write( "------------------------- <BR>\n" );
document.write( "What is the maximum height achieved by the rocket?<BR>\n" );
document.write( "Ans: f(13.125) = 3006.3 ft<BR>\n" );
document.write( "------------------ <BR>\n" );
document.write( "At what time is the rocket at 200ft?<BR>\n" );
document.write( "Solve -16x^2 + 420x + 250 = 200<BR>\n" );
document.write( "x = 26.37 sec<BR>\n" );
document.write( "----------- <BR>\n" );
document.write( "At what time is the rocket at 1500ft?<BR>\n" );
document.write( "Solve -16x^2 + 420x + 250 = 1500<BR>\n" );
document.write( "x = 3.42 sec and x = 22.83 sec<BR>\n" );
document.write( "------------ <BR>\n" );
document.write( "What is the height of the rocket at 3.75 seconds?<BR>\n" );
document.write( "f(3.75) = 1600 ft<BR>\n" );
document.write( "=============<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "-----------  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );