A barking dog delivers about 1.0 mW of power, which is assumed to be

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In summary, the bark of a dog delivers 1.0 mW of power, which is assumed to be uniformly distributed in all directions. The intensity level in decibels at a distance of 5.00 m from the dog is 10-12. The threshold of human hearing is 1.0 × 10-12 W/m2.
  • #1
chemistrymole
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Homework Statement



A barking dog delivers about 1.0 mW of power, which is assumed to be uniformly distributed in all directions. What is the intensity level in decibels at a distance 5.00 m from the dog? The threshold of human hearing is 1.0 × 10-12 W/m2.

Homework Equations



I=P/A A is 4pi(r^2)

The Attempt at a Solution



The only part I am missing is converting the 1 mW to something else so I can plug in the equation above. I tried the 10*log(xxxxxxxx) formula no luck.
 
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  • #2
chemistrymole said:

Homework Statement



A barking dog delivers about 1.0 mW of power, which is assumed to be uniformly distributed in all directions. What is the intensity level in decibels at a distance 5.00 m from the dog? The threshold of human hearing is 1.0 × 10-12 W/m2.

Homework Equations



I=P/A A is 4pi(r^2)

The Attempt at a Solution



The only part I am missing is converting the 1 mW to something else so I can plug in the equation above. I tried the 10*log(xxxxxxxx) formula no luck.

Homework Statement


Homework Equations


The Attempt at a Solution


The power all goes through each spherical surface surrounding the dog. If the sphere has a surface area of 1m^2, then the power flux density is 1.0mW/m^2. If the sphere is a little bigger, and has a surface area of 2m^2, then the power flux density 1.0mW/2m^2 = 0.5mW/m^2.

Does that help?
 
  • #3
No still lost and confused.

Can someone please explain equations further I am not seeing how it connects to the variables given in the question.
 
  • #4
chemistrymole said:
No still lost and confused.

Can someone please explain equations further I am not seeing how it connects to the variables given in the question.

As the sound waves of the bark radiate out from the dog, the 1mW of power (P) gets spread over a progressively larger area (A). At a distance of 5m, what area is it spread over?
 
  • #5
haruspex said:
As the sound waves of the bark radiate out from the dog, the 1mW of power (P) gets spread over a progressively larger area (A). At a distance of 5m, what area is it spread over?

Do I have to convert 1 mW to W?

So would my setup be I = 1/pir^2?

I think my main formula template is I=P/A
 
  • #6
Thanks everyone I found a solution that shows me how to do it. Now I actually understand it and know how the units work.
 

Related to A barking dog delivers about 1.0 mW of power, which is assumed to be

1. How is the power of a barking dog measured?

The power of a barking dog is typically measured in milliwatts (mW). This measurement is based on the amount of energy the dog's bark emits per unit of time.

2. Is 1.0 mW of power a significant amount?

1.0 mW of power is a relatively small amount compared to other sources, such as a lightbulb or a car engine. However, it is still enough to power small devices, such as a watch or a calculator.

3. What factors affect the power of a barking dog?

The power of a barking dog can be affected by various factors, including the size and breed of the dog, the intensity of its bark, and the distance from which the bark is measured. Other external factors, such as background noise, can also impact the perceived power of the bark.

4. How does a barking dog's power compare to other animal sounds?

The power of a barking dog can vary greatly depending on the specific animal and its environment. Generally, larger animals with louder vocalizations, such as lions or whales, will have a higher power output than smaller animals like dogs or birds.

5. Can a barking dog's power be harnessed for practical use?

Currently, there is no known way to harness the power of a barking dog for practical use. However, some researchers are exploring the potential of using animal sounds, including barking, as a source of renewable energy in the future.

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