Chapter 8 You will learn these in college, but I won’t talk about them.
After the self-study class, Liu Ying walked out of the classroom.
During class, a tall figure walked in.
Although the evening is called evening self-study, the courses have been assigned to teachers of each subject. From Monday to Friday, teachers of each subject have an evening self-study.
Today is Thursday. There is a physics class in the evening. The teacher is Shen Yong. He is a Northeastern man. He is a bit fat and has a crew cut. From a distance, he looks like a stunted pear.
"We will try to cover the second model test paper in 2011 in one class, and you will do the questions on your own in the rest of the time."
Shen Yong has a loud voice.
"Questions 1 and 2 are the original questions we have done before. I won't go into detail. For question 3, only three students got it wrong. Ask yourselves if you know it. For question 4, those students who don't know it will raise their hands."
Shen Yong's lectures have always been like this. The answers have been handed out. If there are few people raising their hands, just go ahead. If you come down, ask yourself. If there are many people, focus on the topic.
Xu Qingzhou didn't listen much and read the question from beginning to end. It was simple.
However, being able to write about these topics within a limited framework is actually somewhat interesting.
Xu Qingzhou took out a physics book and opened it to relieve his boredom.
"Question 14. A point charge A is placed on a smooth horizontal surface with a charge quantity of +2×10^6C. At a height of 0.1m directly above it, there is a positively charged small ball with a mass of 0.01kg. Ball B”
"The difficulty of this question is a bit beyond the standard, especially the third question. Our class was wiped out."
Shen Yong opened the thermos cup, drank the wolfberry tea, and asked, "Has anyone solved this problem? Come up and tell me."
He occasionally likes to ask people to speak. Firstly, it can increase the activity of the class. Secondly, it can make the students who speak more divergent thinking. Thirdly, it can refresh their minds. No, the two sleepy classmates below suddenly became energetic.
No one answered, and most of them lowered their heads, worried about being called.
You may not be able to solve a question of this difficulty during the exam, but after reading the answers, some people really don’t know how to do it, some are shy and don’t want to go on stage, and some are just waiting for the teacher to point them out to increase their sense of presence. .
Shen Yong's eyes turned around and fell on Xu Qingzhou.
"Xu Qingzhou, have you made it?"
This kid, after the whole class, I didn't see him listening to the class. He kept flipping through the physics book. If he hadn't gone out and walked around and found that it was indeed a textbook, he would have doubted whether he was reading a novel.
Everyone's eyes were focused on Xu Qingzhou.
Zhang Yuquan felt happy in his heart, let alone letting Xu Qingzhou go on stage. Usually when he was whipped up to answer questions, he stumbled and couldn't explain clearly.
"It's done." Xu Qingzhou closed the physics book.
Guo Ziyang had already begun to mourn for Xu Qingzhou, thinking that it was over. When the paper was handed out to answer the question, Zhouzi was too busy confessing his feelings and did not study the question carefully.
"Then let's talk about it." Shen Yong pointed to the blackboard.
"Okay." Xu Qingzhou nodded, stood up and walked towards the podium.
Guo Ziyang wanted to remind Xu Qingzhou to bring the test paper, but Xu Qingzhou was already 3 meters away.
Zhang Yuquan, who was originally prepared to watch a good show, suddenly had a bad premonition in his heart. The other party's eyes were calm, with a calm and calm look.
Standing on the podium, a long-lost familiar feeling came over me.
In order to do research, it seems that he has not given lectures for more than two years.
Xu Qingzhou picked a piece of chalk from the paper box and said with a smile: "I have three solutions to this question."
This sentence stunned the whole class.
What the hell are three types? Guo Ziyang wondered if he had been doing too much handiwork and had some auditory hallucinations, but he also felt that he was outmatched. He had already quit smoking for a week.
Song Yao's expression was also stunned, her beautiful eyes stared at the calm boy on the stage, a little curious.
Shen Yong held the thermos cup with surprise in his eyes. There were two things he thought of.
Xu Qingzhou continued: "The first two require the use of Maxwell's equations and calculus equations to solve. Only your university will be exposed to them. They are more complicated, so I won't go into them."
Zhang Yuquan's expression froze. If you don't tell me, you're talking nonsense.
Looking at the frustrated expressions of the people below, Xu Qingzhou found that it was fun to pretend to be realistic occasionally.
"I will focus on the third type. First, the electric field strength needs to be calculated. According to the electric field strength formula, we get E=KQ/rE based on Coulomb's law and the equation of motion of ball B." He spoke eloquently and generously.
Underneath, everyone was first amazed at Xu Qingzhou's changes, and then quickly fell into the knowledge points Xu Qingzhou talked about.
Song Yao was the kind of person who looked at the boys on the stage seriously and felt that Xu Qingzhou had been refreshing her impression of him.
Zhang Yuquan's face was expressionless, and the envy, jealousy, and hatred in his heart could no longer be described. This highlight should belong to him!
"Well, it was well explained and very detailed." Shen Yong nodded with satisfaction.
Xu Qingzhou is indeed a talented person. He participated in a physics competition when he was a sophomore in high school. If he hadn't been ill with a high fever, he almost made it to the provincial team. If he works harder, he might also have hope for the national team.
Ding bell, the get out of class bell rang.
"Zhouzi, when did you learn college physics?" Guo Ziyang endured half a class and finally seized the opportunity to speak.
"Find information and educate yourself."
"Holy crap, you're actually studying secretly behind my back!" Guo Ziyang glared.
"This is talent." Xu Qingzhou rolled his eyes, "Besides, what does it mean to study secretly? Except yesterday, when did you miss me when you were surfing the Internet?"
While the two were pulling each other, Shen Yong came over.
"Teacher Shen." they shouted.
"Xu Qingzhou, of the two methods you mentioned, I know that they use Maxwell's equations. What is the other one?" Shen Yong asked curiously.
Xu Qingzhou pulled out a draft and said, "The method of calculating the work done by the electric field force on the ball remains unchanged, but for the potential difference between the two plates of capacitor C, we need to use calculus to solve this problem."
"Therefore, the work W done by the electric field force on the ball is the integral of the electric field force along the motion path of the ball, that is."
Then, the surrounding students saw Xu Qingzhou write a strange formula.
Although I couldn't understand it, I was shocked.
After writing this, Xu Qingzhou stopped writing and looked at Shen Yong. He believed that Shen Yong knew the next steps.
Shen Yong nodded and said with a smile: "This method is quite interesting, but the calculation is a bit heavy."
"Yes, in fact, for high schools, the reference answer is basically the easiest to understand. The other two methods are useful, but they are superfluous." Xu Qingzhou nodded.
High schools use university methods, which are very acclimatized.
For example, if you have to formulate a Euler-Lagrange equation to solve the trajectory of a flat throw, a small ball connected to a rope is released freely horizontally, but you use Fourier transformation to observe whether the process is smooth and differentiable, and then list the radian and A high degree of mathematical relationship
It’s just taking off your pants and farting.
The third period passed quickly and after school, Xu Qingzhou and Guo Ziyang walked out of the school together and separated at a fork in the road.
"I'm back. Where is my dad?"
When Xu Qingzhou entered the door, he saw his mother making dumplings. On the TV was "Sanjie Liu" played by CCTV8.
"I went to have dinner with those little friends." Wang Xiaping was full of resentment.
Every time my father went out to drink, my mother's anger level would be maxed out. He knew enough not to continue the topic, but asked: "What's for dinner?"
"I'm too lazy to cook, so I gnawed on an apple. I just wanted to eat some with you." Wang Xiaping stirred the dumplings in the pot.
Xu Qingzhou threw his schoolbag back into the bedroom and went to the kitchen to help with chores.
After a while, the delicious dumplings were served.
After eating, seeing Wang Xiaping about to put away the bowl, Xu Qingzhou volunteered, "I'll wash it."
"Okay, I'll let you wash every day after the college entrance examination." Wang Xiaping slapped Xu Qingzhou's hand away.
After watching TV with his mother in the living room for a while, Xu Qingzhou was rushed back to the room to review.
Sitting at his desk, he pulled out a notebook.
After adjusting to high school life, it’s time to think about the future.
(End of chapter)