Junior 2 Physics Practice Questions What is sound?

1) When the rubber band is togglerized, the finger action is strong, the amplitude of the rubber band trembling is large, and the volume is strong; When the rubber band is moved, the force of the finger action is small, and the amplitude of the rubber band flutter is small, and the volume is weak.

2) If you fold the rubber band in half (with one-half of the original length), use the same force just now to tighten and then pluck the rubber band, from the two comparisons, you will find that the rubber band in the first phenomenon vibrates slowly, and the sound is low; In the second phenomenon, the rubber band vibrates fast, and the sound is high.

Different objects make different sounds because different objects have different timbres. For example, we can distinguish the sound of a trumpet and a piano based on this characteristic. Like, when someone tells you through the door that he's your parents, I'm sure you won't believe it, right?

Because your parent's voice has a different timbre than his, you can tell that it is not your parent based on this characteristic.

Sound is produced by the vibration of an object, and requires air, solid, and liquid as the medium of transmission: the human throat makes sound, and the vehicle engine makes sound.

Sound is produced by the vibration of an object and travels outward in the form of sound waves.

We can distinguish the sound of the flute and the erhu because of their different timbres, and the different loudness and pitch of the sounds of different objects, so they have different sounds.

For example, if you and I are different objects, will we pronounce them the same?

There are also different sounds from the piano and guitar.

Different objects emit different sounds, which means different timbres.

The sound of the piano and the violin is different, that is, their timbre is different!

The sound is different, that is, the timbre is different, such as everyone's voice is different, and the sound can tell which instrument it is.

Wind music (air sounds).

Strings (solid vocalizations).

1.Everyone's voice is different

2.Each instrument also has a different sound

According to the speed of sound propagation is 340 s, because people stand in the valley, the first time they hear the echo is 1s, so the distance of sound propagation is 340 * 1 = 340m, because it is an echo, so it has to be divided by 2, so 340 2 = 170

The topic is to hear the first time, and then 2s to hear the first hand Chundan twice.

Then the second echo is heard after 3s, and the distance traveled by the sound after 3s is 340*3=1020

Because it's an echo.

So divide by 2 as well

This is not the result, oh, look at it, I just said, people are standing in the valley, and the echo of the second sound is transmitted back from the valley wall where people are farthest away, so the echo from the nearest valley wall of the forest type person is transmitted back after the first 1s, so the total distance of the valley is 170 + 510 = 680m

I guess it's very specific.

Does the landlord understand?

1。The vibrational frequency of the sound heard is the same or regular-——2. The frequency of the sound heard is irregular.

3。Irregular vibration The sound heard is irregular.

The test point of knowing the question is that the regular vibration is the music, and the irregular vibration is the noise. There is also the pitch of the fast turning sound is high because of the high frequency, and the slow turning sound is low because the frequency is low.

I wish you success in your studies.

It should be considered from the rotational speed, and the outermost hole rotates faster than the inner hole when the turntable.

It's just that these feelings ......

Take a closer look at the beauty.

Think about the difference in tone.

1."Place one end of the metal rod against the machine and the other end close to the ear, so that you can hear whether some parts of the machine are normal"The scientific argument that sound travels in solids and loses less energy than in air.

2.This is judged by the pitch of the sound heard. Because the sound produced during filling is the result of the vibration of the air column inside the bottle, the shorter the air column, the higher the tone. When the water level is high enough to produce a specific tone of sound, it indicates that the water is almost full.

1. Solid metal can be used as a sound propagation medium.

2. Liquid can be used as a sound propagation medium.

1. The timbre is different.

2.The timbre is different.

1. Solid propagation sound is better than airborne sound.

2. The air column in the bottle is vibrating, the higher the tone, the shorter the air column, indicating that it is full.

1. Sound propagates best in solids.

2. Different tones (when the water is just poured, the air column in the pot is long and the tone is low; When it is almost full, the air column in the pot is short and the tone is high).

1: Determine whether the timbre is correct.

2: The shorter the air column, the higher the pitch, and the longer the air column, the lower the pitch.

1.Sound waves can carry information 2The water column in the water bottle transmits sound.

The timbre is different, please see the corresponding chapter of the physics textbook, the explanation is very clear.

When the horn is set to leave the mountain S meter 2s, the driver hears the echo The car has gone 2x16=32m, that is, he hears the echo from the mountain (s-32) m

Then s 340 + (s - 32) = 2

Solve s=356m

Then honk the horn 356m away from the mountain, hear the echo 324m away from the mountain

356m

324m Shouldn't you get a tutor!

Personally, I think the first floor is right, this kind of problem will not be the time to find a tutor.

First of all, the speed of the sound is 340m s

Because the distance of 5s sound back and forth is 340*5=1700m, and because it is 900m away from the mountain, the whistle is sounded.

What a classic question! Ha ha.

The speed of sound multiplied by 5 plus the speed of the vehicle multiplied by 5 equals 900 meters by 2 times. Do you understand?