document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1120524>Question 1120524</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An object is propelled vertically upward with an initial velocity of 20 m/s. The distance s (in meters) of the object from the ground after t seconds is given by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%28t%29+=+-4.9t%5E2+%2B+20t+ ALIGN=MIDDLE  ALT=\"+s%28t%29+=+-4.9t%5E2+%2B+20t+\"   DISABLED_style= \"max-width:90%; height:auto;\" >. When will the object be 15 meters above the ground? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #736191 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=736191\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+s%28t%29+=+-4.9t%5E2+%2B+20t+ ALIGN=MIDDLE  ALT=\"+s%28t%29+=+-4.9t%5E2+%2B+20t+\"   DISABLED_style= \"max-width:90%; height:auto;\" >. When will the object be 15 meters above the ground?<BR>\n" );
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document.write( "when s(t) = 20<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20+=+-4.9t%5E2+%2B+20t+ ALIGN=MIDDLE  ALT=\"20+=+-4.9t%5E2+%2B+20t+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4.9t%5E2+-+20t+%2B+20+=+0+ ALIGN=MIDDLE  ALT=\"4.9t%5E2+-+20t+%2B+20+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Solve for t.<BR>\n" );
document.write( "You get 2 times, ascending & descending.<BR>\n" );
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document.write( "Ooooh, 15, not 20.<BR>\n" );
document.write( "The method is the same.<BR>\n" );
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document.write( "If you solve for s(t) = 100, eg, you don't get a real number solution because the projectile never gets to 100 meters.<BR>\n" );
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