document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=925393>Question 925393</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rock is thrown upward with a velocity of 12 meters per second from the top of a 32 meter high cliff, and it misses the cliff on the way back down.  When will the rock be 9 meters from the water, below?\r<BR>\n" );
document.write( "\n" );
document.write( "I used this quadratic equation, &#8722;4.9t^2+2t+32=9 but wasn't sure if it was correct.  I got the answer, 3.71.  Is that the correct answer?  Thanks for taking the time to help me! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #561539 by </B><A HREF=/tutors/aboutme.mpl?userid=rothauserc><B>rothauserc(4718)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=rothauserc><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=rothauserc><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=561539\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> use the following formula<BR>\n" );
document.write( "s(t) = -4.9t^2 + v0t + s0 where vo is velocity and so is the height above ground when thrown, then we have<BR>\n" );
document.write( "9 = -4.9t^2 + 12t +32<BR>\n" );
document.write( "-4.9t^2 +12t + 23 = 0<BR>\n" );
document.write( "use quadratic formula to solve for t<BR>\n" );
document.write( "t = (-12 + square root(12^2 -4*(-4.9)*23) / (2*(-4.9)) = &#8722;1.264134887<BR>\n" );
document.write( "t = (-12 - square root(12^2 -4*(-4.9)*23) / (2*(-4.9)) =  3.713114479<BR>\n" );
document.write( "use t = 3.713114479 approx 3.71 meters<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );