How Long Does It Take to Hear a Stone Hit the Bottom of a Shaft?

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To determine how long it takes to hear a stone hit the bottom of a 122.5 m mine shaft, first calculate the time it takes for the stone to fall, which is approximately 5 seconds. Next, the time for the sound to travel back up the shaft must be calculated using the formula time = distance/velocity. The velocity of sound is given as 343 m/s, allowing for the calculation of the sound travel time. The confusion arises from the need for frequency, which is unnecessary for this calculation as time can be derived directly from distance and velocity. Ultimately, the total time is the sum of the fall time and the sound travel time.
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Homework Statement


Someone drops a stone into a mine shaft 122.5 m deep. How soon after she drops the stone does she hear it hit the bottom of the shaft?


Homework Equations


v= wavelength x frequency


The Attempt at a Solution


I changed the equation to be:
d/t=wf
t=d/wf
t=122.5m/(343m/s x f)

And I'm stuck there...I don't get how to get the frequency

My textbook doesn't even refer to something like this, so I'm extremely confused...It's like asking someone about something they've never learned before...
 
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First you need to figure the time for it to fall 122.5m, then add the time for the sound to return.

Δt = D/Vsound
 
I got the falling part time to be 5 seconds.

And for the time for the sound to return, how do I figure that out? If the velocity for the sound is wavelength x frequency which I have only the wavelength, how can I find the time?
 
t=122.5m/(343m/s x f)
Here f in not needed. time = distance/velocity.
 

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