Hello, Sigma. And welcome back to another video of our video series on kinematics. And this is our third example of our video series on kinematics, where we are going to look at some of the very weird features of relative velocity. So in this problem, as this person stands still on the ground, its velocity is equal to 0, then rainfalls at an angle of 30 degrees to the vertical. As you can easily see, that if this angle is 30 degrees, then this angle would also be 30 degrees. So rainfalls at 30 degrees to the vertical. But as soon as this person starts moving with a velocity, let's say 10 kilometers per hour, then rains starts to fall vertically downwards. Let's just look at this. And this might look very weird at first sight. But actually, this is completely normal. And we all experienced this in our everyday life. Whenever you are traveling by a bike, you would see that normally when you are on the ground, then rain falls vertically down. But as soon as you start traveling in a bike, rains falls directly on your face. So this is completely normal, but what is the physics behind this? As soon as the person starts moving 10 kilometers per hour, then rain falls vertically. And that would imply that the horizontal component of the rain is equal to 10 kilometers per hour. Now, don't freak out. I know that you are confused at this point. How I can say that? But imagine this situation. Let's say you are in a car. This is your car. And there is another car besides you. And you are traveling with some speed V. And that other car is also traveling with the same speed. Right. Then what would happen if you look at the driver of the other car, then you would feel that the driver is that don't look at the car. I know that by common sense, you know, he's car must also be moving since you are driving the car. But if you just look at the driver, then he travels along with you. Right? You all cover equal distance and equal amount of time. That is what equal velocity means. And hence the relative velocity of Yaka with respect to his car would be zero due to which that person would appear at rest. This is the exact logic behind our rain problem. Right? You have a horizontal velocity of 10 kilometers per hour. But as soon and because of that, the rain seems to fall vertically downwards. That means that the horizontal component, this horizontal component of the rain, which is its component, if rain is falling in this direction with some speed V, then the component of this V along the x axis. Let's say if this is the x axis and this is the negative y axis, then the component of rain along the x axis, this is the velocity of the rain. And the component of this of velocity is in this is 30 degrees. The component of this velocity along x direction would be 10 kilometers per hour. That's why when you are traveling at 10 kilometers per hour, the this component, the horizontal component seems to be zero similar to this car analogy. Just like how if you and the other car is moving with the same velocity, the person seems at rest. When you are traveling at 10 kilometers per hour, the horizontal component of the rain, that is, its component in the x direction seems to be zero because the rain's component in the x direction is equal to your velocity in the x direction. And at this moment you might be feeling, yeah, that's not weird at all. Right? So now our task is to find the velocity of rain with respect to ground. So we have to find the question is to find the velocity of rain with respect to the ground. And the velocity of the rain with respect to the man, as the man starts moving, right? This is now we have to find these after the man starts moving. So you can easily see that this vertically falling downwards is the velocity of the rain with respect to the man because as soon as it starts moving, it can only see the vertical velocity as that's told you since the horizontal velocity with respect to the man is zero. So this component of the rain with respect to the man is zero. Right? Vx, I can call it that is zero because they both are traveling at the same velocity with respect to the ground, similar to this car analogy. So it has only the vertical component in the minus y direction. So velocity of the rain, let me call it VRM. But the respect to the man is just equal to velocity of the rain with respect to ground. This V cost 30 degrees, right? It is this component of the velocity, this one, the vertical component. But we do not really know this V, right? So how do we find V? As I told you, the vertical component of this rain has to be equal to 10 kilometers per r, which means that there V, sin 30 is equal to 10 kilometers per. So V is equal to 10 kilometers per r divided by sin of 30 degrees. And that is nothing but 20 kilometers per. So now since we know V, we can substitute this V and this equation, right? So we have found the first answer that is velocity of rain with respect to ground, which would be equal to 20 kilometers per r, V is equal to 20 kilometers per r. And as soon as we substitute it in this equation, we get VRM is equal to 20, cost 30, cost 30 is what root 3 by 2. So that would give us 10 root 3 kilometers. And that finishes our problem. So this might seem weird to you at first sight. But actually I have explained the physics to you and you can see that there is nothing really weird about it. It's all about velocity being a vector. If velocity was a scalar, then it would not behave this way, but since velocity is a vector, you can see how it behaves. And this is not at all like pseudo forces. Many people will confuse this with the pseudo forces, but this is not at all like pseudo forces. Whether the man is stationary or just moving with a constant velocity, Newton's law are valid in both the frames. But when if a man is not in a non-inertial frame, it is accelerating, then Newton's laws will not be valid, which is a very crucial point. So this is not like pseudo forces. It's not that there is some kind of force, which is making this rain fall vertically downwards. After the man starts moving with 10 kilometers for I just not at all like that. This is all about taking components of this velocity. And horizontal component of both the man and the rain being equal due to which he cannot see the horizontal component of the rain, which respectively the man becomes a zero because they have both have the same horizontal component with respect to the ground. Similar to this car analysis, and that's why it sees only the vertical component. So that's it guys. In this video, I wanted to explain to you this very interesting phenomena, which happens due to relative velocity is add velocity is a being a vector. I hope you enjoy the video and to motivate me to create more such interesting videos on such fun concepts of physics and real life examples. Don't forget to hit the subscribe button. I will see you in the next video. Thanks for watching.