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Anonymous users2024-02-11The experimental phenomenon that explains the conditions under which sound is produced is B. Fourth.
Armor. Explain that the propagation of sound requires a medium.
Third. The pitch is determined by the frequency at which the object vibrates.
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Anonymous users2024-02-10A medium is required for the production of sound;
B Sound can transmit energy;
D: Vibrations can produce sound.
Whoo uncertain refer to the lower horn.
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Anonymous users2024-02-09Second. A states that a medium is required for sound propagation (or a vacuum that does not transmit sound), and C states that the pitch is related to the frequency of the object's vibration.
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Anonymous users2024-02-08In order: A.
Sound waves produce energy.
The length of the air column determines the sound of the flute.
The sound-emitting object is vibrating.
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Anonymous users2024-02-07B D. Where A explains: Vacuum cannot transmit sound.
C Description: The pitch of a sound is related to the frequency at which the object vibrates.
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Anonymous users2024-02-06The above experimental phenomenon that illustrates the conditions under which sound is produced is B. Fourth. Other phenomena do not explain the conditions for the production of sounds, but they explain A. Explain that the propagation of sound requires a medium. Third. The pitch is determined by the frequency at which the object vibrates.
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Anonymous users2024-02-05Summary of knowledge of physical acoustic phenomena in junior high school:
1. Sound production:
Sound is produced by the vibration of an object, and the vibrating object is called the sound source; All sound-emitting objects are vibrating, for example, people make sounds by vibrating their vocal cords, wind sounds are sound from air vibrations, bells vibrate by bells, and so on; Sound emitters can be solid, liquid, and gaseous.
2. Sound propagation: selling noisy chang.
The propagation of sound requires a medium, solids, liquids and gases can all transmit sound, in general, sound travels fastest in solids, and gases are the slowest; Vacuum cannot transmit sound, and astronauts on the moon (in space) can only talk through electromagnetic waves; Sound travels in the form of waves (sound waves).
3. Echo: Echo is formed by the sound being reflected back to the middle of the obstacle in the process of propagation. For example, the echo of the mountains, the roar of thunder in summer, and the echo wall of the Temple of Heaven in Beijing.
4. The propagation route of sound in the ear:
The sound from the outside world causes the eardrum to vibrate, and this vibration is transmitted to the auditory nerve through the ossicles and other tissues, and the auditory nerve transmits the signal to the brain, and the person hears the sound.
5. Characteristics of sound:
Musical sound is the sound produced by an object when it vibrates regularly, and the three characteristics of musical sound include tone, loudness, and timbre; The faster the object vibrates, the higher the frequency and the higher the pitch.
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Anonymous users2024-02-04The principle is that the propagation velocity in different media is different, and we know that the propagation speed of sound waves in solids is greater than that in empty molds.
So the first sound should be transmitted by Sun Tiezhong.
The second time is airborne chaining.
The propagation time in air is calculated as t1=s v=170 340=propagation time in iron t2=
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Anonymous users2024-02-03Such as the pin, the bucket base under the finch celebration.
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Anonymous users2024-02-02Let the track length ll 340 - l 5200 = 2l[(1 340)-(1 5200)]=2l=2 * 340*5200) (5200-340)=calculate it yourself.
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Anonymous users2024-02-01Quite simply, the travel time of the rails t1 = l 5400
Air t2=l 340
t1-t2=2
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Anonymous users2024-01-31What do you want to ask Are you doing a task.
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Anonymous users2024-01-30medium, 340, 1700, air vibration (s=vt=340m s*5
Water Pipes Air First Time Second Heard Sound = 170
4 s1 = 1 2vt = 1 2 * 340m s * s2 = 1 2 vt2 = 1 2 * 340m s * s total = s1 + s2 = 34m + 102m = 136m5The higher the frequency, the higher the pitch.
The sound emitter material is different, and the timbre is also different.
Pitch is related to frequency, and timbre is related to emitter material.
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Anonymous users2024-01-29As long as you are 17 meters away from the object, you can hear the echo.
2.Medium 340m s 1700s=vt
Air vibration. 3.Solid (iron pipe) Gas (air) Time taken twice Iron pipe length s2 = 1 2vt2 = 1 2 * 340m s*s total = s1 + s2 = 34m + 102m = 136m5The higher the frequency, the higher the pitch.
The sound emitter material is different, and the timbre is also different.
Pitch is related to frequency, and timbre is related to emitter material.
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Anonymous users2024-01-28Medium 340 1700 Lightning 3, water pipe Air First Second Heard Sound 4 340 * (5
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Anonymous users2024-01-27medium, 340, 1700, air vibration (s=vt=340m s*5
1700m)
3 water pipes, air twice time, distance.
4 s1 = 1 2vt = 1 2 * 340m s * s2 = 1 2 vt2 = 1 2 * 340m s * s total = s1 + s2 = 34m + 102m = 136m5The higher the frequency, the higher the pitch.
The sound emitter material is different, and the timbre is also different.
Pitch is related to frequency, and timbre is related to emitter material.
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Anonymous users2024-01-26Medium 340 1700 Light propagation.
3.Water Pipe Air Length of Steel The propagation time of sound is known v=340ms ,t1= ,t2=
then s=340m s*
34m+102m
136m5.(1) Draw fast and high, and draw slow and low.
2) The comb teeth are sparse and the comb teeth are high.
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Anonymous users2024-01-25c Medium 340 1700 Speed of light Water pipe itself [solid] air Time 340m s
Chapter 1 Acoustic Phenomena.
Relationship between tone and frequency: The higher the frequency, the higher the tone. >>>More
1.Choose C, after many reflections of the mountain clouds on the ground, the actual propagation distance is large and small, so that we can hear thunder many times, in fact, a lightning itself only produces one thunder. For example, if two mirrors are placed opposite each other or at an angle, we can see many images in the mirror. >>>More
Yes, when your velocity is equal to the speed of sound, that is, you are moving forward at the same time with the same sound wave band, which means that the sound waves that your ears receive are all the same, but because the sound waves disappear along the way, the sound you hear will become smaller and smaller until you can't hear it, and the intensity and frequency of the sound determine how long you hear it. If you are moving faster than the speed of sound, i.e. you are chasing the sound wave that has been emitted, you will hear a replay (i.e. reverse), and there may be a sound wave band that has died out by the time you catch it, so you will hear choppy sounds.
Such a topic would not make sense.
This is because of the frequency problem, because the car will have a compression effect on the sound waves during driving, then the wavelength of the sound wave will become shorter and the frequency will increase, at this time the sound you hear is sharper than the original, and when the car drives past you, the sound wave has changed back to the original wavelength and frequency, then at this time you hear a normal sound, and this time is the reason why you feel dull.