document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=43373>Question 43373</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hello!\r<BR>\n" );
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document.write( "Can someone help please?\r<BR>\n" );
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document.write( "My question is:<BR>\n" );
document.write( "Two trains travel in the same direction at 50 kilometres per hour and 32 kilometres per hour respectively. A man in the slower train observes that 15 seconds elapse before the faster train completely passes him.<BR>\n" );
document.write( "What is the length of faster train?\r<BR>\n" );
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document.write( "Thank you for your help and time.<BR>\n" );
document.write( "geomar </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #28385 by </B><A HREF=/tutors/aboutme.mpl?userid=longjonsilver><B>longjonsilver(2297)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=longjonsilver><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=longjonsilver><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=28385\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> from the viewpoint of the man on the slower train, he is stationary and the faster train is going at 18kmph. This is the basics of \"relativity\".\r<BR>\n" );
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document.write( "Anyway, we now have speed and time. We can therefore find the length.\r<BR>\n" );
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document.write( "First we need all numbers to have consistent units. We have speed in kmph and a time in seconds. We need to convert kmph into km per second OR convert the 15 seconds into hours. The second is easier\r<BR>\n" );
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document.write( "Start with something you know:<BR>\n" );
document.write( "60 seconds = 1 minute<BR>\n" );
document.write( "so 1 second = 1/60 minutes<BR>\n" );
document.write( "and hence 15 seconds = 15/60 minutes\r<BR>\n" );
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document.write( "so, 15 seconds = 1/4 minute\r<BR>\n" );
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document.write( "Again, start with something we know:<BR>\n" );
document.write( "60 minutes = 1 hour<BR>\n" );
document.write( "so 1 minute = 1/60 hours<BR>\n" );
document.write( "and hence 1/4 minutes = (1/4)*(1/60) hours\r<BR>\n" );
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document.write( "so 15 seconds = 1/240 hours\r<BR>\n" );
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document.write( "speed = distance/time<BR>\n" );
document.write( "so distance = speed*time<BR>\n" );
document.write( "--> distance = 18*(1/240)<BR>\n" );
document.write( "distance = 0.075km\r<BR>\n" );
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document.write( "and converting this to something more meaningful, we have distance = 75m\r<BR>\n" );
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document.write( "So, length of train is 75m long.\r<BR>\n" );
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document.write( "Jon.<BR>\n" );
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