document.write( "Question 342240: When a rock is dropped from a cliff into an ocean, it travels approximately 16t 2 feet in t seconds. If the splash is heard 6 seconds later and the speed of sound is 1100 ft/sec, approximate the height of the cliff. (Give the answer to two decimal places.) \n" ); document.write( "
Algebra.Com's Answer #244914 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
When a rock is dropped from a cliff into an ocean, it travels approximately
\n" ); document.write( "16t^2 feet in t seconds. If the splash is heard 6 seconds later and the speed of sound is 1100 ft/sec, approximate the height of the cliff. (Give the answer to two decimal places.)
\n" ); document.write( "----
\n" ); document.write( "Time for the rock to hit the water:
\n" ); document.write( "16t^2 = x where x is the height of the cliff.
\n" ); document.write( "t^2 = x/16
\n" ); document.write( "t = (1/4)sqrt(x) sec
\n" ); document.write( "-------------------------
\n" ); document.write( "Time for the sound to travel from the water to the top of the cliff
\n" ); document.write( "= {6-[(1/4)sqrt(x)]} sec.
\n" ); document.write( "----
\n" ); document.write( "Equation:
\n" ); document.write( "distance = rate*time
\n" ); document.write( "----
\n" ); document.write( "distance = 1100 ft/sec*{6-[(1/4)sqrt(x)]} sec.
\n" ); document.write( "---------
\n" ); document.write( "distance = 6600 - (1100/4)sqrt(x)
\n" ); document.write( "x + 275sqrt(x) - 6600 = 0
\n" ); document.write( "---
\n" ); document.write( "Solve for \"x\"
\n" ); document.write( "I graphed the equation and solve for \"x\":
\n" ); document.write( "x = 493.1403 ft.
\n" ); document.write( "=====================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );