Physics the transmission of sound A man stands in the gymnasium and shouts. He hears that the interval between the echoes of the two walls is 0.3 seconds. It is known that the gymnasium is 136 meters long. How many meters are he from the two walls?

Let's set the distance x meters away from the nearest wall and (136-x) meters away from the other wall. With a shout, the sound will bounce back from the wall. The distance of the sound on both sides is 2x meters and 2 * (136-x) meters respectively. The sound speed in the air is 340 meters / second. The equation is 2 * (136-x) / 340 - 2x / 340 = 0.3, and the solution is x = 4

The need of sound transmission In physics we call such a substance ，__ No sound can be transmitted

The transmission of sound needs substance. In physics, such substance is called medium. Vacuum can't transmit sound. So the answer is: substance; medium; vacuum

When one end of the 884m long metal tube is knocked, two sounds are heard successively at the other end, 2.43s apart. What is the propagation speed of sound in the metal tube? What material might the metal tube be made of? Sound velocity V (M / s) Cu 3750 Pb 5000 Fe 5200 in some media

According to v = st, the propagation time of sound in the air is t = sv1 = 884m340m / S = 2.6s; the propagation time of sound in the metal tube is T2 = T1 - △ t = 2.6s-2.43s = 0.17s; the propagation speed of sound in the metal tube is V2 = ST2 = 884m0.17s = 5200m / s; the table shows that the metal tube is made of iron; a: the propagation speed of sound in the metal tube is 5200m / S; the metal tube is made of iron

The transmission of sound
Put the mechanical watch next to the ear (not touching the ear), and the sound you hear is the same as the sound you hear when you put the watch close to the ear_ The sound of the former is mainly through_ The voice of the latter is mainly transmitted through the Internet_ Communication

Air
solid

In ancient times, people often used the method of "listening to the sound on the ground" to judge whether there were horses coming______ I have a lot of knowledge

Because sound can be transmitted in solids, ancient people often used the method of "listening to the sound on the ground" to judge whether there were horses coming

Eighth grade physics Chapter 2 sound phenomenon section 1 sound generation and transmission
For example, liquid can transmit sound
The transmission conditions of sound____ Form of sound transmission .
The propagation speed of sound in 15 ℃ air is_ At room temperature, the sound is The propagation speed is the highest in the The velocity of propagation is the smallest in the medium (filled with solid, liquid or gas)

Diving underwater, you can hear the sound of the shore
The transmission of sound needs medium, and sound cannot be transmitted in vacuum
340m / s solid gas

Physical problems of sound generation and transmission
How do you feel different from your own voice? What do others think? Imagine the reason?

After recording, you can listen to it again. It must be different from listening when you speak. Because when you listen twice, the medium of sound transmission is different
After recording, the sound is transmitted through the air, causing ear tympanic membrane vibration and small bone vibration
Most of what you hear directly when you speak is transmitted through bones, mainly the mandible and skull, and then it is transmitted directly from the auditory nerve to the brain to cause hearing
But what other people hear doesn't make much difference, because they listen to the air twice

On the generation and transmission of sound
In the process of sound production and transmission in the air, it is mainly through the vibration of support that the surrounding air forms a wave of () and spreads around. When it is introduced into the human ear, it will arouse the vibration of the tympanic membrane in the ear, and people will hear the sound. This wave of sound transmission is called ()

Resonance between density and density

On the generation and transmission of sound
Read the speed of sound (unit: M / s) of some media in the table below, air (℃) 331 ice 3230 air (℃) 340 copper 3750 kerosene (℃) 1324 aluminum 5100 water (normal temperature) 1500 iron 5200 (1) what is the law of sound propagation speed in the media? Write two. (2) knock one end of a metal tube about 884m long, and hear two sounds at the other end. How many seconds are the two sounds separated?
Second, when the temperature is 15 degrees Celsius

Laws: 1. The propagation speed of sound increases gradually from gaseous medium to liquid medium and then to solid medium
2. The velocity of the same substance is different in different forms
3. The sound propagation speed of solid medium is related to density
The sound of pipe knocking should be caused by air and metal. The interval time is 884 / 340-884 / 5200 = press the calculator, I'm afraid my hand is not accurate

The generation and transmission of sound
In winter, after a heavy snow, people will feel that everything outside is quiet, even the bustling downtown area is not noisy. However, after the snow is trampled on, nature is back to its former noise. Why?

It turns out that the newly fallen snow is fresh and fluffy. There are many small pores in its surface layer. When the external sound waves enter these small pores, they will be reflected. Because the pores are often large inside and small in diameter, only a small part of the wave energy can be reflected back through the aperture, while a large part of the energy is absorbed. As a result, most of the natural sound energy is absorbed by this surface layer After the snow is trampled on, the situation is very different. The original fresh and fluffy snow will be compacted, thus reducing the absorption of sound energy. Therefore, the nature will return to the past noise

Physics the transmission of sound A man stands in the gymnasium and shouts. He hears that the interval between the echoes of the two walls is 0.3 seconds. It is known that the gymnasium is 136 meters long. How many meters are he from the two walls?