document.write( "Question 1038550: A gentleman jumps out of an airplane without a parachute at 21,980 feet and lives to tell the tale. The function h(t)=-16t²+21,980 describes the relationship between height in feet and the time in seconds. How many seconds did he fall before reaching the ground? \n" ); document.write( "

Algebra.Com's Answer #653253 by Othel(27) $\"\"$ $\"About$

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We can imagine that h(t) in this equation represents the height that the gentleman was located at any point in his fall. We are looking for when the height is equal to 0 feet.
\n" ); document.write( " $\"0=%28-16%29%2At%5E2%2B21980\"$
\n" ); document.write( "Subtracting 21980 from both sides...
\n" ); document.write( " $\"-21980=-16%2At%5E2\"$
\n" ); document.write( "Divide by (-16)...
\n" ); document.write( " $\"%28-21980%29%2F%28-16%29=t%5E2%7D=1373.75\"$
\n" ); document.write( "and taking the square root...
\n" ); document.write( " $\"sqrt%281373.75%29=t\"$
\n" ); document.write( "Since we are looking for the time that it took, we only need the positive square root.
\n" ); document.write( "The time that it took to fall to the ground is approximately 37.06 seconds.
\n" ); document.write( "Check your answer!
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