Sóng cơ và sự lan truyền sóng cơ

The sound of a bell Loud and quiet, noisy and quiet, a river that can't understand itself, a river that finds a way out, that is the sound of Xuan Huynh And today we will learn about the sound of physics We are watching some pictures about sound What is sound? What are the characteristics of sound? What is the description of sound? Physics class 12. Mechanical sound We observe the sound of the water surface We see the surface of the water forming circles and gradually spreading The flow of water on the surface of the water, the source of the sound is the tip of the nose that is moving And this is the flow of sound on the rope We see the flow of sound on the rope Thus, mechanical sound is the flow of sound in an environment People divide sound into two types, horizontal sound and vertical sound First of all, let's find out about the vertical sound Look at the sound of the rope on a spring The points of the spring move along the axis of the spring And the sound also flows along the axis of the spring So, the vertical sound is the sound that the direction of the movement of the particles in the environment coincides with the direction of the sound Sound is also a mechanical sound We will learn more about sound in the next videos The sound in the air is the vertical sound And now, observe the horizontal sound flowing on the spring The points on the spring move up and down while the sound flows along the horizontal direction So, the direction of the movement and the direction of the sound are perpendicular to each other The horizontal sound is the sound that the direction of the movement of the particles in the environment coincides with the direction of the sound The sound on the water surface and on the rope, as you saw in the beginning of the video, is the horizontal sound The horizontal sound is transmitted in the form of snake and the surface of water The vertical sound is transmitted in the form of snake, water and water The mechanical sound is not transmitted in the air How to describe a sound? You have to observe the movement of the boat, it seems like it is coming Take a closer look, it's just moving up and down So, when the sound is transmitted, the particles in the environment only move, not follow the sound Let's look at the case of horizontal sound, that is, the particles in the environment move in harmony The frequency of the sound The frequency of the movement of the boat in this case is also the frequency of the sound The frequency of the sound is the frequency of the movement of the particles in the environment when the sound passes Let's observe the case where the sound has a small frequency and the case where the sound has a large frequency The speed of the sound is the speed of the boat moving It is the speed of the boat moving of the sound peaks marked by the flag as you are watching Once again, you can clearly see that the boat only moves, not the sound, right? The frequency of the sound is the frequency of the movement of the particles in the environment when the sound passes It is the frequency of the boat in a second The unit of the frequency is h There is a frequency that we calculate periodically Lambda wave is an important feature of sound It is the continuous distance between two concentric circles It is also the distance between two continuous waves The unit of the frequency is the distance that the wave can travel in a period The formula to calculate the frequency is lambda equals Vt and equals Vgf The two points on the same side of the concentric circle are closest to each other and move together Then separate by a frequency When the frequency is 1 Hz, the frequency is large If the frequency increases to 2 Hz, the frequency decreases, right? Wave energy is also a characteristic mass of sound It is the wave energy of the particles in the environment when the sound passes The wave process is the wave process of a particle when the sound passes We calculate the horizontal wave in the form of OX The wave process at point O is UO equals ACOTE The wave process of point M by O is UM equals ACOTE minus 2BX divided by lambda Note that the wave process from O to M, so point M will be later than O, which is 2BX divided by lambda The wave process can also be written in the form UM equals ACOTE2B, T divided by T, minus X divided by lambda Let's summarize today's lesson The wave is the motion of the wave in the environment People divide the horizontal and vertical waves based on the motion and wave direction The mechanical wave cannot pass through the vacuum There are 5 characteristic masses of the wave It is the period, frequency, frequency of the wave, the speed of the wave and the wave energy The wave is defined as the wavelength traveled in a period Lambda equals VT equals VGS You have to recognize the wave based on the wave object The wave process is written in the form UM equals ACOTE2B, T divided by 2BX divided by lambda Do you know that light is also a wave? In our history, people have used light from very early on with natural elements such as the sun, the moon, stars and fire Since entering the civilized world, people have begun to debate more about light for questions such as What is light? Where does it come from? How does it go? Do you know that it was not until 1801 that humanity officially recognized the nature of light? Through the experiment of light transfer by Thomas Young, a British physicist, he divided two beams of light into each other The phenomenon occurred exactly like the phenomenon of the interaction of two mechanical waves when these two mechanical waves met The phenomenon of live interaction is a very interesting physical phenomenon We will find out about this phenomenon in the next video Goodbye!