document.write( "Question 149715: When a rock is dropped from a cliff into an ocean, it travels approximately 16t squared feet in t seconds. If the splash is heard 4 seconds later and the speed of sound is 1100 ft/sec, approximate the height of the cliff. \n" ); document.write( "
Algebra.Com's Answer #109854 by ankor@dixie-net.com(22740)\"\" \"About 
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When a rock is dropped from a cliff into an ocean, it travels approximately 16t squared feet in t seconds. If the splash is heard 4 seconds later and the speed of sound is 1100 ft/sec, approximate the height of the cliff.
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\n" ); document.write( "Let t = time it takes for the rock to hit the water
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\n" ); document.write( "(4-t) = time of the sound from the splash to the thrower
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\n" ); document.write( "Write a distance equation; Dist = speed * time
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\n" ); document.write( "Dist falling = distance sound traveled
\n" ); document.write( "16t^2 = 1100(4-t)
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\n" ); document.write( "16t^2 = 4400 - 1100t
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\n" ); document.write( "A quadratic equation:
\n" ); document.write( "16t^2 + 1100t - 4400 = 0
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\n" ); document.write( "Simplify, divide by 4
\n" ); document.write( "4t^2 + 275t - 1100 = 0
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\n" ); document.write( "Solve this using the quadratic formula: a=4; b=275; c=-1100
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\n" ); document.write( "I got a positive solution of about 3.791 sec
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\n" ); document.write( "Find the dist falling (16t^2)
\n" ); document.write( "16(3.791^2) = 229.9 ft
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\n" ); document.write( "Confirm the dist with the sound: 4 - 3.791 = .209 sec for the sound
\n" ); document.write( ".209 * 1100 = 229.9 ft is the cliff height \n" ); document.write( "
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