SÓNG CƠ HỌC LOFI CỰC CHILL || ĐI NGỦ VẪN ĐƯỢC 10 ĐIỂM || THẦY VNA || MAPSTUDY

Hello everyone, today I will teach you the first lesson in the 2nd school of our mechanical life That is the mechanical magnet, this is the opening lesson Give you the most basic definitions, the most basic concepts about life Let us grasp these concepts, I do not do those mathematics, the nature, the theory, the responsibilities In short, so that we can eat the number 1, the number 2 in 5 mechanical life in the university exam You guys, then mention about life, what do you have to mention? Mention about life is that we have to mention the flow of movement, got it? Because life is the flow, got it? If there is no word flow, then no need to learn life, got it? Mention about life is the flow, and flow here is the flow of movement, right? Mention about school 1 is the flow of movement, right? But our life is the flow of movement, right? In space and time, it is more difficult than school 1 So our school of life, people say that the school is difficult to learn because it is abstract, got it? But in fact, is it difficult to learn like this? See straight, no, got it? Learning is still very basic, it is still very easy, but its theory is a bit more than school 1 This school 2 has more theories than straight, see? And its exercise is also quite good and acceptable, so I hope that school 2 will be a strong school for you Not a school that scares you, right? First, we go to the definition of mechanical life Mechanical life is the flow of movement in the atmosphere of the universe It is a flow, and specifically here is the flow of movement in space and time It flows out of the engine like that, but it needs an environment to flow It's as simple as in class 11, you know, electricity can be transmitted because there is an environment Transmitting is the field, right? For example, I often talk to you, right? The sound wave is flowing in the air, it must have an environment to transmit it, right? So the environment that can be transmitted must be the atmosphere of the universe, got it? And it is the movement of the engine, so specifically the movement of the engine here, what does it mean? The movement of the engine has 3 meanings, it is the movement of the movement state Or the movement of the movement, because the movement is the description of the movement state These 2 are 1 to teach us, let us make a theory, just to be responsible And finally, it transmits the movement energy Because when it moves, it will have energy, it transmits the movement energy, right? The engine has the movement energy, got it? It transmits these 3 meanings, and our atmosphere depends on what factors? An environment depends on many factors, let me list some basic factors The atmosphere depends on the temperature of the environment, depends on the temperature of the environment, right? Depends on the force connected to the particles in that environment, right? Different environments will give the speed of movement of the engine in different environments, got it? Because it depends on the material environment, guys So in short, the movement of the engine is the movement of the engine in a complex material environment, got it? So from here, I will have 2 points for you, also from these 2 theories I will go into 2 points right after this Now, I will give you 2 important points, also from these 2 theories The first theory is about the movement of the engine The movement of the engine is the movement of the movement state, the movement of the energy And the engine wave does not move the particles, it does not move the particles, guys But it transmits the state of those particles For example, simply put, if there is a buoy on the surface of the water, right? When the wave passes by, the buoy will only stop and stop, right? That's it, up and down, up and down, where it is But that buoy will not move on the surface of the water, that is the movement of the engine It does not move the particles, got it? So there will be 3 correct ideas on this side and 1 wrong idea on this side If people say which statement is wrong, then the statement that the engine moves the particles is wrong It does not, right? The word does not, does not move the particles, but only moves the state of the particles Next, the wave does not move in the air Because in the air, the density of the particles is very low, almost like we ignore it So I will not say that the wave moves in the air The wave does not move in the air In our air, there is only one wave that we can learn to move That is the electromagnetic wave or the light wave The light wave also has the nature of an electromagnetic wave, it moves in the air, got it? And you can see here a picture of the movement of the wave on the surface of the water Can you see the ball? It is fluctuating And that is the source of the wave, the source of the wave And from that point, the wave will move on the surface of the water The particles of the water are still standing still, right? But the state of it will move And the state goes up and down, it will move on the whole surface of the water, got it? That makes us see the waves fluctuating on the surface of the water And where are those waves coming from? It's because the particles keep going up and down When it goes up to the highest point, we call it the top of the wave When it goes down to the lowest point, we call it the bottom of the wave So you move on to the next image It is a picture of cutting along one side of the wave It is always the same, the image of the wave is going up and down The points are changing positions for each other From the highest point, it will pull the next points up to the highest point That is, its states are fluctuating, right? There, it doesn't move the particles here The particles keep going up and down And its state is moving, right? Look at the top of the particle One point is the top, it will pull to the right of it It is a continuous top, just like that, it keeps moving To emphasize the first point, our wave does not move the particle The particles stay where they are and their states are fluctuating Okay, let's move on to the next part, that is, the type of wave People based on experiments, the type of wave is divided into two types It is a horizontal and a vertical wave Horizontal waves are transmitted in the environment of snake, fluid and gas Vertical waves are transmitted in the snake and the surface of the fluid So you guys look at it, compare it Horizontal and vertical waves will be transmitted in the environment of snakes So if people ask the opposite, they say In the snake, which wave can be transmitted? In the snake, there will be both horizontal and vertical waves You see? So the next opposite If people ask, in the gas, which wave can be transmitted? In the gas, there is a horizontal wave that can be transmitted, but the horizontal wave does not transmit in the gas You see? Horizontal waves also do not transmit in the fluid You see? There, the horizontal wave is in the snake, fluid, gas environment But the experiment shows that the horizontal wave only transmits on the surface of the fluid You see? The surface of the water, the wave on the surface of the water is the horizontal wave You see? Next, the horizontal wave, people see that the particles interact with the direction Here, for example, there is a particle like this, when there is a wave passing through That particle interacts with the direction of the wave, the horizontal direction People call it a horizontal wave Particles interact with the direction Next, the horizontal wave Particles interact with the direction of the wave For example, the wave is like this Particles up and down like this, people call it a horizontal wave Is square with the direction of the wave For example, the waves on the surface of the water, up and down, right? Then it is a horizontal wave People distinguish between horizontal and vertical waves It is based on the direction of the particle interaction and the direction of the wave That is how to distinguish between horizontal and vertical waves Right? In addition, there is the environment, you pay attention In the snake environment, both horizontal and vertical waves can be transmitted The gas is only horizontal And you observe next to it That is the image of horizontal and vertical waves Together in the snake environment, in the spring, right? There, horizontal and vertical waves You see, when they are stimulated together, right? Make the wave spread on the spring The same is the snake, so both waves can be transmitted Right, guys? There, the springs with vertical waves are always in the same direction But with the horizontal wave, it goes up and down It is square with the direction of the wave The waves are divided into two like that Let's make it easy for us to practice Now, let's move on to the next part The characteristics of the E wave I will give you 3 basic characteristics of the E wave It's more, but I only learn about 3 things The first is the frequency of the E wave when it spreads The frequency of the E wave when it spreads is the frequency of the moving particles That is, for example, the source of the wave has a certain frequency Then the particles also have a certain frequency The frequency of the wave is the frequency of the moving particles And the frequency will not change when passing through the environment We can only change the frequency at the source of the wave That is, if we stimulate the wave at the source, but fast The frequency is large, the frequency is slow, the frequency is small Do you hear that? And when it is stimulated and the wave spreads When passing through the environment, the frequency of the wave will not change Do you hear that? OK, that's it And the second characteristic is the speed of the E wave The speed of the E wave depends on the moving environment Please pay attention to this part The speed of the E wave depends on the moving environment The word depends is very important It depends on the moving environment, what does it mean? That is, if the environment changes, the speed will change And if the environment does not change, the speed will not change From here you have 2 notes about the speed That is, in an environment, the speed of the E wave does not change The first note The second note is when there are different environments The speed of the E wave will change For example, the volume of the air is larger than the volume of the air The higher the density, the faster the speed That is, in the sound wave, for example You will know that, for example, if you press your ear to the ground You will hear the sound more clearly than the air That's right, you will find out Right? So you write it down yourself The speed of the E wave in an environment does not change Got it? A homogeneous environment will be a number And when passing through changing environments For example, in the snake environment The snake's volume is larger than the volume of the air V is the speed, you write it down yourself Got it? That's it, okay? An environment, the speed is a number But through the environment, the speed changes Got it? That's why I said that the speed depends on the environment If the environment does not change, the speed does not change The environment changes, the speed will change Got it? So there are two The third characteristic of the mass is the important mass And the first concept I learned about this sound wave is a little different That is, the mass of the sound wave The third characteristic of the mass is the sound wave The sound wave is marked with the letter lambda Read it as lambda, got it? It's the word people write backwards Yeah So The sound wave is the wavelength of the sound wave transmitted within a period That is the definition of the sound wave Simply put, it is the wavelength of the sound wave transmitted within a period Here people often fool you that the sound wave is transmitted in a second It's not like that, got it? But it must be a period, okay? And the step of sound is marked with the letter lambda Lambda is the magnitude of the length So it's the wavelength of the sound wave The sound wave is the wavelength of the sound wave By speed but with time V here is V, the period Here, the sound wave is by V but with T V is V, the period, the speed of the sound wave T is the period of the sound wave T is equal to 1 over F F is the frequency of the sound wave I just studied over there Right? I always get V times T That is V times F Right? So the formula I often use is V times lambda times V times F It is the formula for the speed of sound waves in an environment If you know the frequency or frequency of sound waves in that environment V times lambda times V times F Lambda can be V times T And lambda times V times F Got it? The important part of the definition is The step of sound is the wavelength of the sound that can be transmitted in a period It's a very good conclusion here I just said What is it, guys? Yes, the sound is the sound wave is the transmission by the engine It transmits the state of matter in space and time Here, in space, it transmits exactly what? A step of sound in a period, right? It transmits in space and time To understand this better You will have to learn the part of the G-wave To know the shape of the transmission wave And before you go to accept these definitions Let me do some exercises to get used to it Right? Then you will study the shape of the wave on the string There, you will be more clear about how the actual wave is Got it? And at first I accepted the idea of ​​doing this exercise