document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=252842>Question 252842</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A missile is fired vertically into the air. The distance s (in feet) above the ground as a function of time t (in seconds) is given by the equation below.<BR>\n" );
document.write( "(a) When will the missile hit the ground?<BR>\n" );
document.write( "(b)  When will the missile be 1000 feet above the ground? <BR>\n" );
document.write( "h=300+500t-16t^2<BR>\n" );
document.write( "			 <BR>\n" );
document.write( "I have tried several attempts at this one and nothing!  Anyone willing to help, I would really appreciate it. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #184936 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=184936\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A missile is fired vertically into the air. The distance s (in feet) above the ground as a function of time t (in seconds) is given by the equation below.<BR>\n" );
document.write( "h(t)=300+500t-16t^2<BR>\n" );
document.write( "h(t) is the height of the missile after \"t\" seconds.<BR>\n" );
document.write( "h(0) = 300 is the height from which the missile is launched.<BR>\n" );
document.write( "---<BR>\n" );
document.write( "(a) When will the missile hit the ground?<BR>\n" );
document.write( "When the missile hits the ground the height is zero.<BR>\n" );
document.write( "Solve 300 + 500t - 16t^2 = 0<BR>\n" );
document.write( "75 + 125t - 4t^2 = 0<BR>\n" );
document.write( "t = [-500 +- sqrt(500^2-4*-4*300)]/-8<BR>\n" );
document.write( "t = 31.85 seconds\r<BR>\n" );
document.write( "\n" );
document.write( "(b) When will the missile be 1000 feet above the ground? <BR>\n" );
document.write( "h(t)=300+500t-16t^2<BR>\n" );
document.write( "300+500t-16t^2 = 1000<BR>\n" );
document.write( "-16t2 + 500t - 700 = 0<BR>\n" );
document.write( "-4t^2 + 125t - 175 = 0<BR>\n" );
document.write( "Use the quadratic formula to get:<BR>\n" );
document.write( "x = 29.79 seconds (on the way down)<BR>\n" );
document.write( "x = 1.46 seconds (on the way up)<BR>\n" );
document.write( "======================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
document.write( "\n" );
document.write( "-----------------------<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );