document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=134996>Question 134996</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I do not understand this:\r<BR>\n" );
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document.write( "A ball is thrown vertically upward with an initial velocity of 160 feet per second. The distance in feet of the ball from the ground after 1 second is s=160t-16t^2. For what intervals of time is the ball less than 336 above the ground(after it is tossed until it returns to the ground)\r<BR>\n" );
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document.write( "Good luck and thanks </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #98854 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=98854\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A ball is thrown vertically upward with an initial velocity of 160 feet per second. The distance in feet of the ball from the ground after 1 second is s=160t-16t^2. For what intervals of time is the ball less than 336 above the ground(after it is tossed until it returns to the ground) <BR>\n" );
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document.write( "Find out when the ball is at 336 ft.<BR>\n" );
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document.write( "-16t^2+160t = 336<BR>\n" );
document.write( "Divide thru by -16 to get:<BR>\n" );
document.write( "t^2 - 10t -21 = 0<BR>\n" );
document.write( "(t-7)(t-3) = 0<BR>\n" );
document.write( "t = 3 seconds and t= 7 seconds.<BR>\n" );
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document.write( "The ball is below 336 when 0<=t<3 seconds on the way up.<BR>\n" );
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document.write( "The ball is below 336 when 7<t<10 seconds on the way down.<BR>\n" );
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document.write( "Comment: It hits the ground when t = 10 seconds the time<BR>\n" );
document.write( "up and the time down are symmetric.<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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