Regarding the question of physical acoustics in the second year of junior high school, the question

618 meters. Because sound travels very quickly in iron and slower in air, 314 times 2

2* (speed of sound propagation in iron – speed of sound propagation in air).

Substitute the length of the vested tube s=2*(5000-340)=9320m

Solution:Set iron pipe length s m

.s...s

.= 2s.340m/s...5000m/s

.s = approximately equal to).

.A: The iron pipe is about a meter long.

Because the S 5000 is close to 0, it can be discarded, which is easy to calculate, but this is unscientific. )

Time spent in air: x, steel pipe: x+2, propagation distance in air: 340x m, steel pipe: 5000(x+2) m; That is: 340x m = 5000(x+2) m, the solution is:

680 meters. Analysis: The interval between the two is 2 seconds, because the steel pipe travels faster than the air, then the second time you hear is the sound from the air. So the length of the steel pipe is equal to the speed of airborne propagation multiplied by time!

I'm also in my second year of junior high school, and I've just done this question!

Solution: s=v empty t empty s=v iron t iron.

340m s (t Fe + 2) s = 5000 m s t Fe.

s empty = s iron.

340m s (t Fe + 2) s = 5000 m s t Fe.

t iron s=5000m s

750m A: The length of the iron pipe is 750 meters. That's what our teacher said!

t1=s v empty t2=s v iron.

t1-t2=△t

s v null - s v iron = t

340m s 5000m s 2s (5000m s-340m s) meters.

I don't understand this either! So the first one is recommended!

The first sound is the propagation of iron pipes.

The second sound is airborne.

Multiply time by the speed of propagation of the air.

Students in the distance hear voices that are less loud.

The intensity of a sound is called loudness. Loudness is the strength of the sound judged by the senses, that is, the loudness of the sound, according to which it can arrange the sound in a sequence from light to loud. The magnitude of loudness is mainly dependent on the intensity of the sound and is also related to the amplitude of the sound.

The greater the amplitude, the greater the loudness; The lower the amplitude, the less loudness. In addition, loudness is also related to the distance from the emitter, and the closer to the emitter, the louder it becomes.

2.First empty: ABC

Second empty: gh

Third empty: AD

Fourth space: Adjust the tightness of the strings.

Hit the drum with a small vertical to make a sound, and put the ping pong ball on it, you can see the ping pong ball bouncing up and down, indicating that the occurrence of the object needs to vibrate.

2.Put the 2 3 of the steel ruler on the exposed desktop, and the remaining 1 3 press the exposed desktop part with your hand to press down different amplitudes, and listen to its sound after letting go, indicating that the greater the amplitude, the louder the sound.

(1) (3) Choose a string of suitable length, pluck the string vigorously, feel the pitch of the string, and then tighten the string appropriately, pluck the string with the same force, feel the pitch of the string again, and compare the pitch of the string before and after.

1) Selected equipment: steel ruler and wooden comb.

2) The main experimental procedure: take a steel ruler and use different forces to swipe over the teeth of the wooden comb, and listen to the sound made by each wooden comb.

3) The physics you designed to illustrate is that the pitch of a sound is related to frequency (I hope it helps you, and I hope you can!). )

Question 1: aStudents in the distance hear voices that are less loud.

Question 2: In order to verify conjecture 1, the numbers (a) (b) (c) should be selected In order to verify conjecture 2, the numbers (c), (e), (g) should be selected In order to verify conjecture 3, fill in the missing data should be length 80 cross-sectional area.

As the experiment progressed, Xiaohua felt that the pitch of the strings might also be related to the tightness of the strings, and in order to verify this conjecture, the operations that had to be carried out were: (Adjust two or three strings with equal cross-sectional area or equal length to different tensions and then pluck them).

3. The following equipment is now given to you: a steel ruler, a wooden comb, a tuning fork, a table tennis ball (tied to a string), a rubber band, a drum, a paper, and a small hammer. Please design an experiment on acoustic phenomena with your choice of equipment.

1) Selected equipment: tuning fork, table tennis ball (tied with string), small hammer.

2) Main experimental steps:1Start by striking the tuning fork with a small hammer. 2.Touch the ping-pong ball tied to the string to the tuning fork that is making a sound. 3.See how the ping-pong ball (will bounce off).

3) The physics you are trying to illustrate in your experiment is that sound is produced by vibrations.

The third question is a tuning fork, a table tennis ball and a tether, a small hammer. A person puts a table tennis ball on top of this fork and hits the tuning fork with a small hammer, and he will see that the table tennis ball will move, indicating that the sound cause can transmit wave energy.

Loudness refers to the size of the sound heard, the timbre is to distinguish the sound, the frequency affects the tone, the smaller the amplitude, the smaller the loudness, and here the main thing is the distance 2（1）abc adf（3）80 3.Drums, small hammers, paper Tear the paper into pieces and put it on the drum and hit the paper with a hammer, and the beating sound is generated by vibration.