The speed of sound wave propagation, the speed at which sound travels

This involves a basic formula. v = under the root number (kp d).

V is the velocity of the sound wave in the gas, K is the adiabatic coefficient of the gas, P is the pressure of the gas, and D is the density of the gas.

From this formula, the upstairs are all wrong, because the bigger the d, the smaller the v. For example, at the same pressure, sound travels faster in hydrogen than in oxygen. The density does not change, the temperature is increased, the pressure can be increased, and the speed of sound propagation can be increased.

For the formula v=under the root number (p d), you can refer to the university tutorial on physics and mechanics.

The propagation velocity in different media is different, and the velocity in air is about 340m s

If I remember correctly, junior high school physics says 343m s. at 15 degreesAt 25 degrees it is 346m s

Mach 1 is about 340 m-s, or 1,224 km-h.

Mach is a measure word that indicates speed, also known as Mach number. One Mach is twice the speed of sound (speed of sound).

where u is the velocity of flow and c is the speed of sound. The speed of sound is the speed at which pressure waves (sound waves) travel through a fluid. The Mach number was named in honor of the Austrian scholar Ernst Mach (1838-1916).

Mach is generally used in aerospace vehicles such as airplanes and rockets. Since the speed of sound propagation in the air varies with different conditions, the Mach is only a relative unit, and the specific velocity of each "Mach" is not fixed. The lower the speed of sound propagation at low temperatures, the lower the specific velocity corresponding to Mach 1.

Therefore, it is relatively easier to achieve a higher Mach number at high altitude than at low altitude.

On October 14, 1947, Jaeger flew the X-1 test aircraft over southern California to break away from the B-29 parent aircraft, ascend to an altitude of 12,000 kilometers, and reached a speed of 1,078 kilometers per hour at this altitude, breaking the sound barrier for the first time, exceeding Mach 1.

When the Mach number is <, the pressure on the fluid is not enough to compress the fluid, and only causes the flow of the fluid. In this case, the density of the fluid does not change with pressure, and this flow field is called subsonic flow, which can be considered an incompressible flow field. Ordinary water currents and atmospheric air flows, such as turbulent rivers, typhoon wind fields, and the movement of automobiles, are incompressible flow fields.

However, when the fluid is moving at high speed (the flow rate is close to or greater than the speed of sound), the density of the fluid will change with the pressure, and the flow of the gas at this time is called the compressible flow field. When the Mach number MA is >, it is called supersonic flow, and this type of flow is encountered in aerodynamics.

The relationship between the speed of sound and temperature in air:

v=331 root number (1+t 273)(m s).

t: is the temperature in Celsius; v: The speed of sound at t.

There is also an introduction to the relationship between the speed of sound and temperature:

The speed of sound is also the speed of sound, which is the speed at which sound travels through a medium. Sound waves can travel in solid, liquid, or gaseous media, and the denser the medium, the faster the speed of sound. In air, the speed of sound varies depending on the state of the air (e.g., humidity, temperature, density).

For example, the speed of sound at sea level at zero degrees Celsius is about.

km/h)；The speed of sound at 10,000 meters is about 295 m s (1062 km h); In addition, for every 1 degree Celsius increase, the speed of sound increases.

The higher the temperature, the greater the speed of sound.

After repeated tests, it was found that the speed of sound in water is affected by temperature. Seawater contains salts, and the amount of salt has an effect on the speed of sound. Among the various factors, temperature has the greatest influence on the speed of sound, and for every 1 increase, the speed of sound in water increases by about milliseconds.

The speed of sound in seawater is thought to be 1,500 meters per second, which is about twice the speed of sound in the atmosphere.

Scientists have also measured the speed of sound in various liquids. At 20, the speed of sound in pure water is meters and seconds; The speed of sound in mercury is 1451 m/s; The speed of sound in glycerol is 1923 m s; The speed of sound in alcohol is 1168 ms and in carbon tetrachloride liquid is 935 ms. It can be seen that sound travels much faster in liquids than in the atmosphere, which is closely related to the molecules in the liquid.

The speed of sound in solids also varies, and after repeated measurements, it is found that sound waves propagate in solids in the form of longitudinal waves and transverse waves, and the wave velocities of these two waves are also different. For example, in stainless steel, the longitudinal wave velocity is 5790 m/s and the transverse wave velocity is 3100 m/s. The stainless steel is made into a rod, and the longitudinal wave velocity inside the rod is 5000 meters per second.

In metals, beryllium is an expert at sound transmission, and the longitudinal wave speed of sound waves reaches 12,890 meters per second in rods made of beryllium, which is 38 times that of atmospheric sound transmission. The longitudinal wave speed in the polyethylene rod is only 920 meters per second, which is not as fast as the sound speed in the water. The soft rubber is elastic, and the sound waves cannot move in it, and the speed is only 30-50 meters per second, which is less than the speed of sound in the air!

The air is dense and the speed of transmission is large! The high temperature is high, and the speed of propagation is small!

The speed of propagation of sound in different media is as follows:

1. Air: The propagation speed of sound in the air at 0 degrees Celsius is 331 m s, in the air at 15 degrees Celsius is 340 m s, and in the air at 25 degrees Celsius it is 346 m s. It can be seen that the speed of sound propagation in the air varies with the change of temperature, and the speed of sound rises or falls by 3 m s for every 5 degrees Celsius rise or fall in temperature.

2. Cork: 500m s

3. Kerosene (25 degrees Celsius): 1324m s

4. Distilled water (25 degrees Celsius): 1497m s

5. Seawater (25 degrees Celsius): 1531m s

6. Ice: 3230m s

7. Copper (rod): 3750m s

8. Marble: 3810m s

9. Aluminum (rod): 5000m s

10. Iron (rod): 5200m s

Sound cannot travel in a vacuum.

Factors influencing sound propagationThe most critical factor in the transmission of sound is the medium. The medium refers to all solids, liquids, and gases, which is a prerequisite for sound to be able to travel. The physical parameters are related to the distance of the sound source from the observer, the vibration frequency of the sound source, and the propagation medium.

The propagation speed of sound increases with the increase of the toughness of the substance, and decreases with the decrease of the density of the substance, such as: the propagation speed of sound in ice is faster than that of sound in water, the toughness of ice is stronger than that of water, but the density of water is greater than that of ice, which reduces the gap between the propagation speed of sound in water and ice.

It has been measured that the speed of sound waves is 344 meters per second in the air at room temperature and pressure, 1430 meters per second in light dust front water, 1500 meters per second in seawater, 5800 meters per second in steel, 6400 meters per second in aluminum, 5370 meters per second in quartz glass, and only 30 to 50 meters per second in rubber.

When the temperature and pressure of the medium change, the speed of sound also changes. When the temperature drops to zero, the speed at which sound waves travel through the air will be meters per second, and the speed of sound will increase by meters per second for every 1 degree Celsius increase.

The frequency of the sound waves of ordinary conversation between 500-2000 Hz. The frequency of sound waves that can be heard by the human ear is generally between 20 Hz (Hertz) and 20 kHz.

Depending on the frequency of the sound waves, it can be divided into the following categories:

1. Sound waves with a frequency lower than 20Hz are called infrasonic waves or ultra-low sounds;

2. Sound waves with a frequency of 20Hz and 20kHz are called audible sounds;

3. Sound waves with a frequency of 20kHz and 1GHz are called ultrasonic;

4. Sound waves with a frequency of 1GHz are called ultrasound or microwave ultrasound.

Brief introduction. Sound begins with the vibrations of air particles, such as those produced by guitar strings, human vocal cords, or speaker paper cones. Together, these vibrations push adjacent air molecules and slightly increase the air pressure.

The air molecules under pressure then push the surrounding air molecules, which in turn push the next group of molecules, and so on.

When a high-pressure area passes through the air, it leaves a low-pressure area behind. When these pressure wave changes reach the human ear, they vibrate the nerve endings in the ear, and we hear these vibrations as sounds.

The above content refers to Encyclopedia - Sound Waves.

The propagation speed of sound waves is about Zebu Wei ().

a.330 meters per second.

b.3300 meters per second.

c.30,000 meters per second.

d.300 kilometers per second.

Zhengsun Pei's answer: a

The propagation velocity of sound in the air is: air (15) 340 m s, air (25 ) 346 m s. Sound varies according to the speed of propagation in different substances.

The propagation of sound is also related to temperature and resistance, as well as different densities. It affects the speed at which sound travels.

Sound is a pressure wave: when a musical instrument is played, a door is slammed or a table is struck, their vibrations cause the medium-air molecules to vibrate rhythmically, causing the surrounding air to produce dense changes to form sparse longitudinal waves, which produce sound waves, and this phenomenon continues until the vibration disappears.

As a kind of wave, frequency and amplitude have become important properties to describe the wave, the magnitude of the frequency corresponds to what we usually call pitch, and the amplitude affects the magnitude of the sound. Sound can be broken down into superpositions of sine waves of different frequencies and intensities. This process of transformation (or decomposition) is called the Fourier transform.

Therefore, sound in general always contains a certain frequency range. The frequency range of sounds that can be heard by the human ear is between 20 and 20,000 hertz. Fluctuations above this range are called ultrasound, while those below this range are called infrasound.

Animals such as dogs and bats can hear sounds up to 160,000 hertz. Whales and elephants produce sounds with frequencies in the range of 15 to 35 Hz.

The propagation of sound is explained by quantum mechanics as the movement of atoms, which forms sound waves. But this is not related to nouns such as wave particles.

The propagation velocity of sound in the air is: at 15, it is 340m s; At 25, it was 346m s.

The speed of sound propagation in the air is also related to pressure and temperature, the propagation of sound requires substance, such a substance is called a medium in physics, the speed of sound in the air changes with the change of temperature, the temperature rises and falls by 5, and the speed of sound rises and falls by 3m s.

Note: The most critical factor for sound propagation is to have a medium, which refers to all solids, liquids and gases, which is the premise for sound to be propagated. The physical parameters are related to the distance of the sound source from the observer, the vibration frequency of the sound source, and the propagation medium.

The propagation speed of sound increases with the increase of the toughness of the substance, and the density of the substance decreases, for example: the propagation speed of sound in ice is faster than that of sound in water, the toughness of ice is stronger than that of water, but the density of water is greater than that of ice, which reduces the gap between the propagation speed of sound in water and ice.

1. The propagation speed of sound in the air is: air (15) 340m s, air (25) 346m s.

2. Different water propagation velocities are different, distilled water (25) 1497m s, seawater (25) 1531m s. Copper (rod) 3750m s, aluminum (rod) 5000m s, iron 5200m s.

3. Sound varies according to the speed of propagation in different substances. The propagation of sound is also related to temperature and resistance, as well as different densities. It affects the speed at which sound travels.