document.write( "Question 989420: A person of height 1.68 m is walking away from a lamp-post at 1.5 m/s. The light on the lamp-post is 5.3 m above the ground. \r
\n" ); document.write( "\n" ); document.write( "At what rate (in m/s to the nearest cm/s) is the length of the person's shadow changing?\r
\n" ); document.write( "\n" ); document.write( "s/5.3 = (s-p)/1.68
\n" ); document.write( "1.68 s = 5.3 s - 5.3 p
\n" ); document.write( "3.62 s = 5.3 p
\n" ); document.write( "s = 1.464 p
\n" ); document.write( "ds/dt = 1.464 dp/dt
\n" ); document.write( "but dp/dt = 1.5
\n" ); document.write( "so
\n" ); document.write( "ds/dt = 2.196 m/s \r
\n" ); document.write( "\n" ); document.write( "This answer was incorrect, I am not sure where I went wrong?\r
\n" ); document.write( "\n" ); document.write( "The next part of the question:\r
\n" ); document.write( "\n" ); document.write( "At what speed (in m/s to the nearest cm/s) is the tip of the person's shadow moving across the ground?\r
\n" ); document.write( "\n" ); document.write( "And I assume to get this, I take the answer from the first part, and add 1.5?\r
\n" ); document.write( "\n" ); document.write( "I have tried many ways but keep getting the first part incorrect \r
\n" ); document.write( "\n" ); document.write( "THANK YOU \n" ); document.write( "

Algebra.Com's Answer #609753 by thesvw(77) $\"\"$ $\"About$

You can put this solution on YOUR website!
It took me sometime to understand what went wrong. Your answer represents the rate of changing S which is not the mans shadow. It is the addition off mans shadow and the distance man went from the post. After little calculations I got this expression, s-p= 1.68*p/(5.3-1.68)\r
\n" ); document.write( "\n" ); document.write( "You will get it. You just misunderstood. \n" ); document.write( "

\n" );