How Far Did the Parachutist's Impact Occur from the Swimmer?

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Homework Help Overview

The problem involves a swimmer observing a parachutist's impact with the water and hearing the sound of the impact twice, once through water and once through air, with a time delay of 1.0 seconds between the two sounds. The subject area is related to sound propagation in different mediums and the calculation of distance based on time and speed of sound.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the relationship between distance, speed of sound, and time taken for sound to travel through air and water. They explore how to express the time taken for sound to travel in each medium in terms of distance and question the calculations leading to the proposed answer.

Discussion Status

Participants are actively engaging with the problem, questioning the assumptions made about the time differences and the calculations involved. Some have provided partial reasoning and expressed confusion about the results, indicating a lack of consensus on the correct distance.

Contextual Notes

There is a noted discrepancy in the proposed answer, with participants questioning the accuracy of the calculations and the assumptions regarding sound speed in different mediums. The discussion reflects an exploration of the problem rather than a resolution.

whatwhat11
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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 :confused:
 
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whatwhat11 said:
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 :confused:

This is a straightforward rate x time = distance (r t = d) problem.

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?)
 
Chestermiller said:
This is a straightforward rate x time = distance (r t = d) problem.

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?)

Vsound in air= (340)(2)
=680m

V sound in water = (1400)(1)
=1400

1400-680
doesn't equal 450m or 459m
 
whatwhat11 said:
Vsound in air= (340)(2)
=680m

V sound in water = (1400)(1)
=1400

1400-680
doesn't equal 450m or 459m

Hu?

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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