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 #184939 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=184939\">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( "(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( "Reordering:<BR>\n" );
document.write( "h=300+500t-16t^2<BR>\n" );
document.write( "h=-16t^2+500t+300<BR>\n" );
document.write( "(a) When will the missile hit the ground?<BR>\n" );
document.write( "Set h to 0 and solve for t:<BR>\n" );
document.write( "h=-16t^2+500t+300<BR>\n" );
document.write( "0=-16t^2+500t+300<BR>\n" );
document.write( "0=-4t^2+125t+75<BR>\n" );
document.write( "Applying the quadratic equation we get:<BR>\n" );
document.write( "t = {-0.59, 31.84}<BR>\n" );
document.write( "The negative solution doesn't make sense -- so, throw it out leaving us with:<BR>\n" );
document.write( "t = 31.98 seconds<BR>\n" );
document.write( ".<BR>\n" );
document.write( "(b) When will the missile be 1000 feet above the ground?<BR>\n" );
document.write( "set h = 1000 and solve for t:<BR>\n" );
document.write( "h=-16t^2+500t+300<BR>\n" );
document.write( "1000=-16t^2+500t+300<BR>\n" );
document.write( "0=-16t^2+500t-700<BR>\n" );
document.write( "0=-4t^2+125t-175<BR>\n" );
document.write( "Applying the quadratic equation we get:<BR>\n" );
document.write( "t = {1.47 secs, 29.78 secs}<BR>\n" );
document.write( "The first time is on the way up<BR>\n" );
document.write( "and the second time is on the way down.\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );