 Longitudinal, right? Now, move, got it? Okay? So, and then they are going down also. Same part, up and down, a periodic motion. Got it? A part of it is periodic? No, C wave, sir. Asniki is FBC. Okay? So, if you should play with it, then it's okay. You might just be playing with it. Sound is a longitudinal wave. To some other player, from your sound, it is a combination of how... So, that is, does that, like, gets down to be the one who starts? Is that better? No, no, it's not. See, shh. That's a, it's taking me a role to start and then that's how it starts. Are you aware of what it has? Because that's what it is coming about, why the sound? Okay. Get down. It applies some force on heavy mass and trying to shake it and then I'm trying to shake it. Okay? You can say, what is, what will happen after this time? How much is the velocity after this much displacement? What will be the final location of a part? I should know better what is the characteristic of a wave. So, please do not, you can't use equation of motion. It's an energy that is transmitted from one position to the other position. Okay? So, please write down frequency. So, it says that correct. So, when, when I'm speaking, the societies where we're not saying velocity, we're saying speak. One by one, please, three things and try to understand more about it. First, please talk about what happens. That is the initial position, which means position should be positive. So, that is why one complete oscillation is that when everything repeats wave, fine, it one oscillation. It's a time taken, time taken to complete one oscillation. If the time period is a time period of oscillation. So, if time taken to, does it make sense? In t seconds, one oscillation. So, in one second, one by t oscillations. Okay? So, one by t, it sends to now, okay? Now, compression is there. Here, compression, air fraction is there. So, it is difficult. So, okay? So, this is what we do. Suppose this is the frequency also, fine? But it is the number of times to consider one half of the pass of the forms through this obstacle. Point of one will not come back in the net and pass, right? It will just pass and go away. So, importantly, we are closer to, just look at it. Can it define the frequency? It will help. So, frequency is frequency, frequency of...