document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=988387>Question 988387</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The height of a projectile fired upward with an initial velocity if 400 feet per second is given by the formula h=-16t^2+400t, where h is the height in feet and t is the time in secounds. Find the time required for the projectile to return to earth. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #608949 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=608949\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Find the time to the highest point and double it.<BR>\n" );
document.write( "That is the vertex of a quadratic equation, which x value (t here) is -b/2a=-400/-32=12.5<BR>\n" );
document.write( "So the vertex is at 12.5 seconds, and the time to Earth is 25 seconds.<BR>\n" );
document.write( "The maximum height will be 2500 feet.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28400%2C400%2C-10%2C30%2C-100%2C3000%2C-16x%5E2%2B400x%29 ALIGN=MIDDLE  ALT=\"graph%28400%2C400%2C-10%2C30%2C-100%2C3000%2C-16x%5E2%2B400x%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );