document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=765101>Question 765101</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The formula for the height (in feet from the starting point) reached after t seconds by an object thrown upward at r feet per second is h=rt – 16t^2. So for an object thrown upward at 160ft/sec, h=160t-16t^2\r<BR>\n" );
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document.write( "after how many seconds will the object first be 336ft above its starting point?\r<BR>\n" );
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document.write( "how high will the object be after 4 seconds?<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 #465961 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=465961\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The formula for the height (in feet from the starting point) reached after t seconds by an object thrown upward at r feet per second is h=rt – 16t^2. So for an object thrown upward at 160ft/sec, h=160t-16t^2<BR>\n" );
document.write( "after how many seconds will the object first be 336ft above its starting point?<BR>\n" );
document.write( "start with:<BR>\n" );
document.write( "h=160t-16t^2<BR>\n" );
document.write( "set h to 336 and solve for t:<BR>\n" );
document.write( "336=160t-16t^2<BR>\n" );
document.write( "dividing both sides by 16:<BR>\n" );
document.write( "21 = 10t-t^2<BR>\n" );
document.write( "t^2+21 = 10t<BR>\n" );
document.write( "t^2-10t+21 = 0<BR>\n" );
document.write( "(t-3)(t-7) = 0<BR>\n" );
document.write( "t = {3, 7}<BR>\n" );
document.write( "the object will be at 336 feet twice (once on the way up and again on the way down) at:<BR>\n" );
document.write( "3 seconds and 7 seconds<BR>\n" );
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document.write( "how high will the object be after 4 seconds?<BR>\n" );
document.write( "start with:<BR>\n" );
document.write( "h=160t-16t^2<BR>\n" );
document.write( "set t to 4 and solve for h:<BR>\n" );
document.write( "h=160(4)-16(4)^2<BR>\n" );
document.write( "h=640-16(16)<BR>\n" );
document.write( "h=640-256<BR>\n" );
document.write( "h= 384 feet </SPAN>\n" );
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