document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=268286>Question 268286</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help with this problem, this is what I have so far:\r<BR>\n" );
document.write( "\n" );
document.write( "Problem: Height of a projected ball, <BR>\n" );
document.write( "An astronaut on the moon throws a baseball upward. The astronaut is 6ft., 6in. tall, and the initial velocity of the ball is 30 ft. per sec. The height S of the ball in feet is given by the equation<BR>\n" );
document.write( "S= -2.7t^2 + 30t + 6.5<BR>\n" );
document.write( "where t is the number of seconds after the ball was thrown.\r<BR>\n" );
document.write( "\n" );
document.write( "A.) After how many seconds is the ball 12ft above the moon's surface? Round to the nearest hundreth.\r<BR>\n" );
document.write( "\n" );
document.write( "I know I have to look for the seconds, which is t so then I have to solve for S, the height. This is have I've got so far:<BR>\n" );
document.write( " 12 = 2.7t^2 + 30t + 6.5<BR>\n" );
document.write( "-12                 -12<BR>\n" );
document.write( "------------------------<BR>\n" );
document.write( "  0 = 2.7t^2 + 30t - 5.5<BR>\n" );
document.write( " <BR>\n" );
document.write( "B.)How many seconds will it take fore the ball to return to the surface? Round to the nearest hundredth.\r<BR>\n" );
document.write( "\n" );
document.write( "So on the second part of the equation I have to look for the time, so that means that I have to solve for the height...<BR>\n" );
document.write( " <BR>\n" );
document.write( "Thanks for your help in advance. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #196655 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=196655\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A.) just use the quadratic formula on the equation you generated and solve for t<BR>\n" );
document.write( "___ watch the signs (your equation has an incorrect sign for the coefficient of the squared term)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "B.) substitute zero for S in the original equation (S= -2.7t^2 + 30t + 6.5) and use the quadratic formula\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "check the solutions for t to see if they make sense<BR>\n" );
document.write( "___ A should have two solutions (upward and downward)<BR>\n" );
document.write( "___ B should have one solution (negative value not realistic) </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );