document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=869917>Question 869917</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I have no idea on this question . I dont know what they want me to graph : a toy rocket is launched from a platform 20 feet above the ground with an initial velocity of 128 feet per second. The equation for the height{in feet} of the rocket t seconds after being launched is  h= -16t^2+128t+20 <BR>\n" );
document.write( "The graph of the height equation is? <BR>\n" );
document.write( "a} Do i need vertex ,x interception and y interception? <BR>\n" );
document.write( "b} from the question the equation should be 20=-16t^2+128t+20 ?<BR>\n" );
document.write( "thank you </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #524553 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=524553\">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=+graph%28+300%2C+200%2C+-25%2C+25%2C+-300%2C+300%2C+-16x%5E2%2B128x%2B20+%29+ ALIGN=MIDDLE  ALT=\"+graph%28+300%2C+200%2C+-25%2C+25%2C+-300%2C+300%2C+-16x%5E2%2B128x%2B20+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "This is a parabola with time (t) along the x axis and height (h) along the y axis.  From the graph, the rocket looks like it achieves max height of 260 feet after 4 seconds.<BR>\n" );
document.write( "Also, you can use calculus and take the first derivative and set it equal to 0 to determine the time t for the max height.<BR>\n" );
document.write( "f' = -32t + 128<BR>\n" );
document.write( "-32t + 128 = 0<BR>\n" );
document.write( "32t = 128<BR>\n" );
document.write( "t = 4<BR>\n" );
document.write( "now we can determine the max height by subsituting for t in oringal equation<BR>\n" );
document.write( "h = -16*4^2 +128*4 + 20 = 266 feet<BR>\n" );
document.write( "the vertex of the parabola is (4, 266)<BR>\n" );
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