Cliff Height Calculation: Rock Drop & Sound Travel

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To calculate the height of a cliff from which a rock is dropped, the total time taken for the rock to hit the ocean and the sound to travel back must be considered. The rock falls under gravity, while the sound travels upwards at a constant speed of 340 m/s. The problem can be broken down into two time intervals: the time of free fall (t1) and the time for sound to travel back (t2). Using the equations of motion for free fall and the speed of sound, the height of the cliff can be determined. This approach effectively combines both the physics of falling objects and sound propagation.
monkeyboy726
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rock is dropped from cliff. it is heard hitting the ocean 3.00s later, if speed of sound is 340m/s, how high is the cliff?

im so stuck
 
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try d= (at^2)/2
a = acceleration
t = time
d = distance
use the speed of sound in dry air at sea level to solve.
 
Hi -

This is how I would approach this problem...

Draw a sketch to represent the situation. As you can see, the rock is in free fall from y (the height of the clift to the ground) to the ground (y = 0). The soundt travels with uniform speed the distance y (upward). Let t1 be the time of the free fall and t2 the time of the sound traveling up. Then, the total time is t = t1 + t2 = ?. Then, use the free fall formula to get time t1 and then solve for the height of the clift.

Good luck :smile:
 

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