document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=150310>Question 150310</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If an object is thrown upward with an initial velocity of 64 ft/sec, its height after t sec is given by h = 64t - 16t2. Find the number of seconds the object is in the air before it hits the ground. \r<BR>\n" );
document.write( "\n" );
document.write( "I figure that it would work with d=rt but I don't know how to convert it to this assignment. what throws me off is the h=64t-16t2... </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #110289 by </B><A HREF=/tutors/aboutme.mpl?userid=scott8148><B>scott8148(6628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=scott8148><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=scott8148><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=110289\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> because of gravitational acceleration, r is constantly changing __ that makes d=rt not useful in this situation\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "when it is on the ground, h=0 __ so we can substitute and solve\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "0=64t-16t^2 __ factoring __ 0=(16t)(4-t)\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "0=16t __ dividing by 16 __ 0=t __ this is the beginning of the \"flight\"\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "0=4-t __ adding t __ t=4 __ this is the \"flight\" time </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );