document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1199344>Question 1199344</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A model rocket is launched from a platform. The trajectory of the<BR>\n" );
document.write( "rocket can be modelled by the relation h=−5t^2+100 t+15, where h is the<BR>\n" );
document.write( "height of the model rocket in meters and t is the time in seconds.<BR>\n" );
document.write( "a) What is the height of the platform?<BR>\n" );
document.write( "b) What is the height of the model rocket after 4 seconds?<BR>\n" );
document.write( "c) What is the maximum height reached by the rocket? How long does<BR>\n" );
document.write( "it take to reach this height?<BR>\n" );
document.write( "d) Approximately how long is the rocket in the air?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #833188 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=833188\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the equation is h = 5^2 + 100t + 15.<BR>\n" );
document.write( "h is the height of the rocket.<BR>\n" );
document.write( "t is the time in seconds.\r<BR>\n" );
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document.write( "the height of the platform is the height when t = 0 which is 15 meters high.\r<BR>\n" );
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document.write( "the height of the rocket after 4 seconds is found by replacing t with 4 and solving for h.<BR>\n" );
document.write( "you get h = -5 * 4^2 + 100 * 4 + 15 = 335 meters.\r<BR>\n" );
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document.write( "the maximum height reached by the rocket is when t = -b/2a.\r<BR>\n" );
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document.write( "a = the coefficient of the t^2 term = -5<BR>\n" );
document.write( "b is the coefficient of the t term = 100<BR>\n" );
document.write( "c is the constant term = 15\r<BR>\n" );
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document.write( "t = -b/2a becomes t = -100 / -10 = 10<BR>\n" );
document.write( "when t = 10, h = -5 * 10^2 + 100 * 10 + 15 = 515 meters.\r<BR>\n" );
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document.write( "it takes 10 seconds for the rocket to reach the maximum height.\r<BR>\n" );
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document.write( "the equation can be graphed by letting y represent h and x represent t.<BR>\n" );
document.write( "here's what the graph looks like.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" src = \"http://theo.x10hosting.com/2022/122301.jpg\">\r<BR>\n" );
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