2 Sound waves reflection easy problems

In summary, the question involves counting claps in relation to intervals and determining the correct time interval for each clap. For question 21, the answer is 1.1 seconds, not 0.5 seconds, and for question 22, the correct answer is C because the first reflected pulse travels 2h and the second reflected pulse travels 4h. The speed of sound in water is greater than the speed of sound in air, making answer A impossible. The correct answer for question 21 is B, not A.
  • #1
Clara Chung
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14

Homework Statement


Refer to the photos, question 21 and 22(the one with a helicopter)

Homework Equations


Both answers are A

The Attempt at a Solution


for question 21, if the counts to ten, there are 9 intervals. I divide 20 by 9 and divide it again by 2 and get 1.1s not 0.5s.
for question 22. I think it is C. Because the first reflected pulse has traveled 2h and the second reflected pulse has traveled 4h. I think it is impossible for the answer to be A, the pulse should travel slower in water.
 

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  • #2
For Q21, if the first clap is associated with the count of zero, wouldn't there be 10 intervals?
For Q22, the speed of sound in water is greater than the speed of sound in air.
 
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  • #3
lewando said:
For Q21, if the first clap is associated with the count of zero, wouldn't there be 10 intervals?
For Q22, the speed of sound in water is greater than the speed of sound in air.
But 20/10(2) = 1s?
 
  • #4
That is true. That result matches answer B. I can't see how A could be correct.
 
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  • #5
Actually I misread the question. Only claps are being counted.
 
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  • #6
lewando said:
Actually I misread the question. Only claps are being counted.
Oh thanks I can do it now
 

1. What is a sound wave?

A sound wave is a type of mechanical wave that is created by a vibrating object and travels through a medium, such as air, water, or solid objects. It is characterized by its frequency, wavelength, and amplitude.

2. How is sound reflected?

Sound is reflected when it encounters a boundary with a different medium or a change in density within the same medium. This causes the wave to change direction and bounce off the surface, similar to how light is reflected off a mirror.

3. What is the law of reflection for sound waves?

The law of reflection for sound waves states that the angle of incidence (the angle at which the sound wave hits the surface) is equal to the angle of reflection (the angle at which the sound wave bounces off the surface). This law applies to all types of waves, including light and sound waves.

4. How does the shape of an object affect sound wave reflection?

The shape of an object can affect sound wave reflection in several ways. If an object has a smooth surface, the sound wave will reflect off it at the same angle as it hit the surface. However, if the object has a curved or irregular surface, the sound wave may scatter in different directions, leading to diffuse reflection.

5. How can we calculate the distance of an object using sound wave reflection?

We can calculate the distance of an object using sound wave reflection by measuring the time it takes for the sound wave to travel to the object and bounce back to the source. This is known as the time-of-flight method and is commonly used in sonar and ultrasound technology.

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