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Quick speed of sound question? 
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#1
Dec2012, 06:14 AM

P: 14

A swimmer sees a parachutist hit the water and hears the impact twice, once through the water and the second time through the air, 1.0 s later. How far from the swimmer did the impact occur?
Vs air = 340 m/s Vs water = 1400 m/s the answer is 450m I don't understand what to do 


#2
Dec2012, 06:54 AM

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Let d = distance from swimmer to splash point. In terms of d, how much time does the sound take to get from the splash point to the swimmer in air? In terms of d, how much time does the sound take to get from the splash point to the swimmer in water? In terms of d, what is the difference between these two times? (Actually, the answer is not 450m, it's only 449m, but who's counting?) 


#3
Dec2012, 08:26 AM

P: 14

=680m V sound in water = (1400)(1) =1400 1400680 doesn't equal 450m or 459m 


#4
Dec2012, 01:26 PM

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P: 5,402

Quick speed of sound question?
The answer to my first question was: the amount of time it takes for the sound to travel through the air from the splash to the swimmer is d/340 seconds The answer to my second question was: the amount of time it takes for the sound to travel through the water from the splash to the swimmer is d/1400 seconds The answer to my third question was: the difference between these two times is (d/340)  (d/1400) =1 second Are you able to solve this equation for the distance d? If so, what do you get for d? 


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