document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=128542>Question 128542</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please please please help me.\r<BR>\n" );
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document.write( "1) A missile is fired into the air from a 100 ft hilltop such that its height above ground after ‘t’ seconds is given by the equation: h(t) = 100 + 800t – 16tsquared<BR>\n" );
document.write( "a) Find the time interval for which the missile is at least 9700 ft above ground level. <BR>\n" );
document.write( "b) Determine after how many seconds the missile will hit the ground.<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #94054 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=94054\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 1) A missile is fired into the air from a 100 ft hilltop such that its height above ground after ‘t’ seconds is given by the equation: h(t) = 100 + 800t – 16tsquared<BR>\n" );
document.write( "a) Find the time interval for which the missile is at least 9700 ft above ground level. <BR>\n" );
document.write( "-16t^2+800t+100=9700<BR>\n" );
document.write( "-16t^2+800t-9600 = 0<BR>\n" );
document.write( "t^2-50t+600 = 0<BR>\n" );
document.write( "(t-20)(t-30)=0<BR>\n" );
document.write( "t=30 ; t=30<BR>\n" );
document.write( "The missile is at or above 9700 ft between 20 and 30 seconds<BR>\n" );
document.write( "after launch.<BR>\n" );
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document.write( "b) Determine after how many seconds the missile will hit the ground.\r<BR>\n" );
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document.write( "-16t^2+800t+100=0<BR>\n" );
document.write( "-4t^2+200t+25 = 0<BR>\n" );
document.write( "t = (-200 +- sqrt(200^2-4*-4*25)]/-8<BR>\n" );
document.write( "Positive solution:<BR>\n" );
document.write( "t = (-200 - sqrt(40400)]/-8<BR>\n" );
document.write( "t = 50.12 seconds<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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