document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=711321>Question 711321</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi, could you perhaps shed some light on this problem? \"Sky divers are in free fall from the time they jump out of a plane until they open their parachutes. A sky diver jumps from 5000 feet. The diver's height 'h' above the ground 't' seconds after the jump is described by the equation 'h=-16t^2 (squared)+ 5000.' Find the time during which the diver is in free fall assuming that the parachute opens at 1000 feet.\" Where did the -16t^2 come from? and where does the 1000ft distance come in? Any help would be greatly appreciated!<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 #437430 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=437430\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Sky divers are in free fall from the time they jump out of a plane until they open their parachutes.<BR>\n" );
document.write( " A sky diver jumps from 5000 feet.<BR>\n" );
document.write( " The diver's height 'h' above the ground 't' seconds after the jump is described by the equation 'h=-16t^2 (squared)+ 5000.' <BR>\n" );
document.write( "Find the time during which the diver is in free fall assuming that the parachute opens at 1000 feet.\" <BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h%28t%29+=+-16t%5E2+%2B+5000 ALIGN=MIDDLE  ALT=\"h%28t%29+=+-16t%5E2+%2B+5000\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-16t^2 represents the average downward attraction to the earth by gravity<BR>\n" );
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document.write( "You start at 5000 ft, you want the free fall to end at 1000 ft (parachute opens)<BR>\n" );
document.write( "therefore h(t) = 1000, find how many seconds for this to happen<BR>\n" );
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document.write( "-16t^2 + 5000 = 1000 <BR>\n" );
document.write( "subtract 5000 from both sides<BR>\n" );
document.write( "-16t^2 = 1000 - 5000<BR>\n" );
document.write( "-16t^2 = -4000<BR>\n" );
document.write( "t has to be positive, multiply both sides by -1<BR>\n" );
document.write( "16t^2 = 4000<BR>\n" );
document.write( "divide both sides by 16<BR>\n" );
document.write( "t^2 = 250<BR>\n" );
document.write( "find the square root of both sides<BR>\n" );
document.write( "t = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%28250%29 ALIGN=MIDDLE  ALT=\"sqrt%28250%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "t = 15.811 seconds to fall to 1000 ft </SPAN>\n" );
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