As soon as the teacher left the classroom, Guo Chaozhan immediately asked Ye Fan: "Ye Fan, do you understand what the teacher said about this lesson? This math subject is the subject I hate the most, if I want to say it might as well be cancelled, last year it was because I didn't pass the math that I was only in the fourth grade now, ahhhhh

Ye Fan looked at Guo Chaozhan's embarrassing portrait from the side, and couldn't help but feel a little funny, of course, he was still a little puzzled: This doesn't seem to be too difficult? The logic of mathematics refers to the fact that mathematics is a rigorous subject, and there must be no sloppiness in the process, while intuitive analysis and construction refers to the breadth and profundity of mathematics, not only one problem but only one solution, so we need to explore, general and individual means that when learning mathematics, we should neither think too complicated nor too simple, but do the problem with a normal heart. Today's first lesson is actually to introduce us to mathematics and how to learn mathematics. Okay, the next physics class is really hard, you better listen to it yourself. ”

"Hello students, I am your physics teacher, you can call me Teacher Jiang, just like last semester, this semester my class (kuo) representative is still our fifteenth classmate Jiang Zhe (zhi). Now let's start the class. Today we are learning about pressure. In other words, pressure is the amount of force per unit area acting perpendicular to the surface of the object. It is also a physical quantity that represents the effect of pressure action (deformation effect). In the International System of Units, the unit of pressure is Pascal, or Pascal for short, which was named in honor of the French scientist Pascal, i.e., Newton/square meter. The common units of pressure are kilopascals, megapascals, kilograms-force per square centimeter, torr, etc. Pa is generally represented by the English alphabet (PA).

Generally speaking, there are two formulas for pressure, one is p=f/s, and the other is p=ρgh, and the pressure at the bottom, inner wall, and inside of the liquid container is called liquid pressure, referred to as hydraulic. We know that an object is subjected to a force that produces pressure, and as long as an object has pressure on the surface of another object, there is pressure, and in the same way, water has pressure on the bottom of the container due to the action of gravity, so there is pressure on the bottom of the container. The liquid has fluidity and has pressure on the wall of the container, so there is pressure on the wall of the container as well.

There is pressure in all directions inside the liquid, and the pressure increases with the increase of the depth of the liquid, and the pressure of the same liquid at the same depth is equal in all directions; the pressure of different liquids at the same depth is related to the density of the liquid, and the greater the density, the greater the pressure of the liquid. Okay, that's it for today, wait for the cultivation class, and now the class will be over. As everyone knows, the classmates below are already smiling.

When the time came for class, Ye Fan didn't rush to the cultivation classroom, but stayed in the classroom to get to know his classmates, after all, they had to live together for a year, and they couldn't call that stupid thing when they were separated.

After the communication and understanding of the class, coupled with the help of Guo Chaozhan, Ye Fan finally got to know most of the students clearly and also understood the situation of the class. There are a total of 71 people in the class, and he is now No. 71, oh no, when he just got out of class, Mr. Shi had already come over to inform Ye Fan that he was now the 25th, of course, he didn't know how this boring student number was arranged, and he didn't want to know. And his tablemate, Guo Chaozhan is No. 31, the middle stage of the Yellow Order, and Wu Baobao behind him is No. 54, the middle stage of the Yellow Order. As for him, he was assigned to the Wu Bubble Group, Wu Bubble is the team leader, Yu Yutong is the deputy leader, and there are four Yellow Order Mid-Stage Xiaocheng in the group, two Yellow Order Mid-stage Dacheng, plus two Yellow Order Mid-Stage Perfection, oh and himself, this team has a total of nine people, which is not bad in the class.

Stepping on the bell, Ye Fan finally rushed to the cultivation classroom. As soon as he entered the classroom, he found that there were seventy-one eyes staring at him, and when he looked up, Yu Yutong, the deputy leader of the group, waved his hand anxiously at him, obviously not wanting to embarrass him. Ye Fan pursed his lips, leaned towards Yu Yutong helplessly, and came to Wu Baobao's group, only to hear Wu Baobao ask him in a low voice: "Ye Fan, where have you been?" Teacher Shi's temper is not very good, pay attention next time." ”

Ye Fan nodded, indicating that he understood, and was waiting to reply. Teacher Shi has already started to speak: "Today we are going to talk about some basic essentials, as well as practicing a book of exercises. There are three conditions for practicing qigong - loose, quiet, and natural practice must have three conditions - loose - relaxation, tranquility and naturalness are the most basic requirements in the process of qigong training. Regardless of the type of exercise, the stage of practice must meet this basic criterion. Generally speaking, in the process of practicing, it seems very simple to be relaxed, but it takes a lot of effort to truly understand and do it.

Loose refers to the relaxation of the whole body and mind. People live in nature and society, and when they wake up, they are affected by various external environmental factors, and their minds and bodies are often in a state of tension, which makes it difficult for the body to function normally, and even leads to the emergence of various diseases. Therefore, in practicing the exercises, we should first start by eliminating the state of tension, putting aside the hard work of the world and the worries of life, and first relaxing the spirit as much as possible. Only when the mind is not nervous can the body be truly relaxed. The so-called relaxation of the body is not completely relaxed, lax or loose and weak, but loose and unremitting, loose and tight, tight but not stiff. Each exercise has certain requirements for posture, and in order to maintain a certain posture, a certain muscle group must be in a state of tension, which seems to contradict practicing relaxation. In fact, the muscle tension at this time is to maximize the relaxation of each muscle and unify the contradictions on the premise of maintaining the posture. In the early stage of practice, because it is required to have a certain amount of mental activity to eliminate distracting thoughts, this state and mental relaxation should also be unified, and it is not easy to do at the beginning of the practice, but after a period of time, it will gradually become loose and tight, tight but not stiff.

Tranquility refers to the state of "meditation" in which distracting thoughts are relatively reduced and highly quiet, relaxed and comfortable during the practice process. The depth of meditation reflects the quality of the practice and is directly related to the effect of the practice, and the details of this have been discussed in the section on meditation in this book. It should be pointed out that relaxation and tranquility are required and mutually reinforcing at the same time, and relaxation can help to enter meditation, and meditation can further relax. There should be a relatively quiet environment for the practice, and the Jinggong should be practiced at home as much as possible, not outside. Because when practicing, all the veins are open, and the sweat pores are also open, and it is easy to be exposed to wind outside. It is better to practice the general kinetic and pile skills outside. It is best if there is no movement in the practice place, and it doesn't matter if there is a little sound, as long as there is no sudden loud noise, our practice is to get used to being quiet in the middle of noisy, which is kung fu in itself, and it is real kung fu. Practicing the exercises in an environment where there is a sound requires us to close our four doors tightly, not to look out and not to see out, not to hear and not to hear, not to smell and not to smell, and not to lose our minds. After a long period of cooking, it can naturally be quiet.

We should try our best to choose a quiet environment for our practice, our hearts like to be quiet, and our kidneys should be safe. Practicing in a quiet environment can make the practitioner calm and relaxed, which is conducive to meditation. With the deepening of skills, you can gradually eliminate external interference, take quiet in the middle of noisy, and increase your resistance to adversity. When the kung fu is practiced to the point that the heart is lonely and empty, spotless, the heart is like a rock wall, and the towering ten thousand miles, even if Mount Tai collapses in front and the Yellow River is decided, it is naturally immovable. Many people always feel that they are not suitable for practice, saying that they can't calm down, but in fact, this is a misunderstanding. At the beginning of our practice, we were all distracted, and none of us could calm down at once, so we all had to train repeatedly. In the practice, I am not afraid to read it, but I am afraid of being late. I am not afraid of distracting thoughts, but I am afraid that I will not be vigilant. When a thought comes, we have to be aware, immediately cut off the thought, and the process of constantly eliminating distracting thoughts is practice. That's all for today, how to comprehend it depends on your own understanding, of course, I also hope that everyone will gain something. Let's start practicing the exercises and judge the best teams for this lesson. ”