document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1178898>Question 1178898</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Grade 10- The height of a ball thrown upward after a given amount of time is h = - 4.9t ^ 2 + 29.4t + 1 where h represents the height of the ball in metres , and t represents the time elapsed since the ball has been thrown . Determine the maximum height of the ball and at what time this occurs. What is the maximum height reached by the ball? How long is the ball above a height of 40 m ? When does the ball hit 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 #808352 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=808352\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the vertex t value is at -b/2a or -29.4/-9.8 or 3 seconds<BR>\n" );
document.write( "the maximum height is at h(3)=-44.1+88.2+1=45.1 m<BR>\n" );
document.write( "solve for h=40<BR>\n" );
document.write( "so -4.9t^2+29.4t+1=40<BR>\n" );
document.write( "and -4.9t^2+29.4t-39=0<BR>\n" );
document.write( "or 4.9t^2-29.4t+39=0<BR>\n" );
document.write( "t=(1/9.8)(29.4+/-sqrt (99.96); sqrt term=10.0<BR>\n" );
document.write( "t=1.98 sec and t=4.02 sec<BR>\n" );
document.write( "it is above 40 m for 2.04 sec<BR>\n" );
document.write( "it hits 0 at -4.9t^2+29..4t-1=0=4.9t^2-29.4t+1<BR>\n" );
document.write( "the positive root is t=(1/9.8)*(29.4+sqrt883.86); sqrt term=29.73<BR>\n" );
document.write( "t=6.03 sec\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=graph%28300%2C300%2C-10%2C10%2C-10%2C50%2C40%2C-4.9x%5E2%2B29.4x%2B1%29 ALIGN=MIDDLE  ALT=\"graph%28300%2C300%2C-10%2C10%2C-10%2C50%2C40%2C-4.9x%5E2%2B29.4x%2B1%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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