document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=192305>Question 192305</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Anobject that is projected straight downward with initial velocity v  feet per square travels a distance s=vt+16tsquared,where t=time in seconds. If Ramon is standing on a balcony 84ft above the ground and throws a penny straight down with an initial velocity of 10ft per second,in how many seconds will it 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 #144403 by </B><A HREF=/tutors/aboutme.mpl?userid=RAY100><B>RAY100(1637)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=RAY100><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=144403\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> s=vt+16t^2\r<BR>\n" );
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document.write( "84=10t+16t^2<BR>\n" );
document.write( "subt  84  both  sides\r<BR>\n" );
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document.write( "0=16t^2+10t-84<BR>\n" );
document.write( "factor <BR>\n" );
document.write( "0=2(8t^2+5t-42)\r<BR>\n" );
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document.write( "factor  bracket  using  quadratic  eqn<BR>\n" );
document.write( "a=8,  b=5,  c=-42\r<BR>\n" );
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document.write( "t= (-(5) +- sq  rt ( (-5)^2-4 (8) (-42) )/2(8)\r<BR>\n" );
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document.write( "t=(-5+- sq rt ( 25 + 1344) )/16\r<BR>\n" );
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document.write( "t= (-5 +- sq rt (1369) 0/16\r<BR>\n" );
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document.write( "t=  (-5 +- 37)/16\r<BR>\n" );
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document.write( "t=  (-5-37)/16=-2.625    not  realistic,  neg  time\r<BR>\n" );
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document.write( "or  t= (-5+37)/16=  +2\r<BR>\n" );
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document.write( "checking\r<BR>\n" );
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document.write( "s=vt+16t^2\r<BR>\n" );
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document.write( "84=10(2) +16(2^2)=20+62=84  ok </SPAN>\n" );
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