document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=732150>Question 732150</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a particle sliding down an inclined plane travels 2 feet the first second. In any second after the first it slides 4 feet farther than it did in the preceding second. how far will it slide in 7th second? how far will it slide in 7 seconds? how long will it take to slide 128 feet? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #447574 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=447574\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a particle sliding down an inclined plane travels 2 feet the first second. In any second after the first it slides 4 feet farther than it did in the preceding second. how far will it slide in 7th second? how far will it slide in 7 seconds? how long will it take to slide 128 feet?\r<BR>\n" );
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document.write( "t1=2 =a\r<BR>\n" );
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document.write( "t2=2+4=6\r<BR>\n" );
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document.write( "t3=6+4=10\r<BR>\n" );
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document.write( "a=2<BR>\n" );
document.write( "d=4\r<BR>\n" );
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document.write( "tn= a+(n-1)d<BR>\n" );
document.write( "t7=2+(7-1)4\r<BR>\n" );
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document.write( "t7= 26,  26 feet in the 7th. second\r<BR>\n" );
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document.write( "Sn=n/2[2a+(n-1)d]\r<BR>\n" );
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document.write( "S7=7/2[2*2+(7-1)4]\r<BR>\n" );
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document.write( "S7=7/2[28]\r<BR>\n" );
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document.write( "S7=98,   98 feet in 7 seconds\r<BR>\n" );
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document.write( "128=n/2[4+(n-1)2]\r<BR>\n" );
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document.write( "256=4n\r<BR>\n" );
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document.write( "256=4n +2n^2 -2n\r<BR>\n" );
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document.write( "2n^2+2n-256=0<BR>\n" );
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document.write( "n^2+n-128=0<BR>\n" );
document.write( "solve the quadratic for x\r<BR>\n" );
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document.write( "you will get n=10.82 \r<BR>\n" );
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document.write( "In 10.82 sec it will go 128 feet </SPAN>\n" );
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