document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=201491>Question 201491</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/020132458x/algebrahomeworkh>algebra 1 expressions,equations, and applications</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> an astronaut on the earth practices jumping to the ground from the spaceship resting 3 meters above the ground. the initial upward velocity of the jump is 4 m/sec.<BR>\n" );
document.write( "a. when will the astronaut be back at the same level s the jump?<BR>\n" );
document.write( "b. at what time is the highest point reached?how high above the ground is that?<BR>\n" );
document.write( "c.when does the astronaut reach 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 #151757 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=151757\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> In metric units, g = 9.8 meters/sec/sec<BR>\n" );
document.write( "Height as a function of time:<BR>\n" );
document.write( "h(t) = -9.8t^2 + 4t + 3<BR>\n" );
document.write( "Set h = 3 to find the times at 3 meters.<BR>\n" );
document.write( "3 = -9.8t^2 + 4t + 3<BR>\n" );
document.write( "9.8t^2 - 4t = 0<BR>\n" );
document.write( "t = 0<BR>\n" );
document.write( "t = 4/9.8 = ~ 0.408 seconds<BR>\n" );
document.write( "----------------<BR>\n" );
document.write( "b) The easiest way to find this is divide the time back at 3 meters by 2, since he travels up to apogee in the same time it takes to get back to 3 meters.<BR>\n" );
document.write( "t at max height = 0.204 seconds<BR>\n" );
document.write( "Max height = h(0.204)<BR>\n" );
document.write( "hmax = ~ 3.40816 meters above ground, not above where he jumped from<BR>\n" );
document.write( "------------------------------<BR>\n" );
document.write( "Set h = 0 for the time at ground level (3 meters below the start point)<BR>\n" );
document.write( "9.8t^2 - 4t - 3 = 0<BR>\n" );
document.write( "t = 0.7938 seconds </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );