document.write( "Question 865782: An arrow is launched upward with a velocity of 128 feet per second from the top of a 100-foot building. What is the maximum height attained by the arrow? \n" ); document.write( "

Algebra.Com's Answer #521850 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+h%28t%29+\"$ = the height of the arrow in feet
\n" ); document.write( " $\"+h%28t%29++=+-16t%5E2+%2B+128t+%2B+100+\"$
\n" ); document.write( "------------------------------
\n" ); document.write( "This is a parabola of the form:
\n" ); document.write( " $\"+y+=+ax%5E2+%2B+b%2Ax+%2B+c+\"$
\n" ); document.write( "If the max height is at ( t[max], h[max] )
\n" ); document.write( " $\"+t%5Bmax%5D+=+-b%2F%282a%29+\"$
\n" ); document.write( " $\"+a+=+-16+\"$
\n" ); document.write( " $\"+b+=+128+\"$
\n" ); document.write( " $\"+t%5Bmax%5D+=+-128%2F%28+2%2A%28-16%29%29+\"$
\n" ); document.write( " $\"+t%5Bmax%5D+=+4+\"$
\n" ); document.write( "Plug this result back into equation to get $\"+h%5Bmax%5D+\"$
\n" ); document.write( " $\"+h%5Bmax%5D++=+-16%2A4%5E2+%2B+128%2A4+%2B+100+\"$
\n" ); document.write( " $\"+h%5Bmax%5D+=+-256+%2B+512+%2B+100+\"$
\n" ); document.write( " $\"+h%5Bmax%5D+=+356+\"$ ft
\n" ); document.write( "--------------------
\n" ); document.write( "Here's the plot:
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-2%2C+12%2C+-40%2C+450%2C+-16x%5E2+%2B+128x+%2B+100+%29+\"$
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