In a small classroom, Xie Qi closed the door, opened the window, sat on the podium, and took a cigarette.

This series of actions is done in one go, and there is no feeling of a cultured person.

This is probably the legendary ruffian.

Li Zheng's behavior was completely opposite to him, he put away his schoolbag, stationery, notebook, and sat upright.

Xie Qifen looked at this series of actions, and couldn't help but sigh: "I'm just about to get a national-level three-good student for you." ”

"Ah, there are still national-level ones?" Li Zheng was inevitably eager to try.

Xie Qi smiled and said: "Yes, all, and world-class, go to Moscow to judge, Lenin will award the award." ”

"Boring. Li Zheng thought for a moment, and quickly found something wrong, "No, you're talking about this is an excellent league member, right?"

“…… You're really ...... Quite seriously. Without further ado, he lit a cigarette and asked, "What part of physics do you want to hear?" ”

"Huh? I just want to hear about quantum. Li Zheng said and picked up the stationery and sat in the back row of the classroom, which made it taste smaller.

"Quantum mechanics is a pyramid scheme, and those people don't know what to do. Xie Qifen resolutely waved his hand and said, "Hurry up, change another." ”

"Then listen to what you specialize in. Li Zheng replied.

Xie Qifen waved his hand more resolutely: "No, you don't understand what I'm doing, and I'm too lazy to talk about it until you understand, even if you understand, it's not good for your future." ”

Li Zheng complained: "Why do you have so many things to do when you give a lecture." ”

"I'm going to talk nonsense about perpetual motion machines. ”

"Don't, don't, don't ......" Li Zheng scratched his head and said, "Then let's talk about fluid mechanics, I don't learn this part very well." ”

"Normal. Xie Qifen said with a cigarette in his mouth, "Lagrange's description, Euler's description, Bernoulli's equation are all known, right?"

"Yes, but not deeply. ”

"Then let me ask you, what do these brothers have in common?"

"Well......" Li Zheng replied almost without much thought, "they are all mathematicians." ”

"Eh, that's right!" he puffed out his cigarette and jumped off the desk, and walked to the blackboard, "Turning the laws of physics into mathematical equations, and then cutting the fluid into small pieces, and solving them with calculus ideas, this is fluid mechanics, of course, this is just the way of Lagrange, and Euler's method is wilder." One more thing, all physics problems can be solved with this routine if you want to. ”

"Ahh Li Zheng's eyes widened, "Isn't this the ...... See the wind?"

"Yes, I've heard about him from the Academy. Xie Qifen nodded, "His understanding of physics concepts is basically limited to high school textbooks, and has always been turned into mathematical ideas to solve problems. ”

"Alas...... Don't mention him. Li Zheng urged, "You can continue to speak." ”

"Well, I'll give you a description of Lagrange first. He drew a diagram on the blackboard, which was probably a puddle of water, cut it into pieces in a differential way, and then drew a series of schematic diagrams of the force.

"This is the most basic physical image of fluid analysis. ”

"We need to use physical images as a hub to connect the mathematical world. ”

"Of course, top geniuses don't need this, they have their own translation system in their brain circuits. ”

"For example, von Neumann, he also did this, but he did it when he was building the atomic bomb with Fermi and Feynman, when the brothers and sisters got together to calculate, Fermi was old and used a slide rule, Feynman was young, he used a computer, von Neumann didn't use anything, he just did mental arithmetic, and the result was always faster than the old guys. ”

"Then the atomic bomb experiment was successful, and the two brothers went home after finishing their work, and as a result, von Neumann mentally calculated a 'Neumann stability analysis' by the way, which directly blossomed in mathematics and physics, but unfortunately it was thought up by the way when the atomic bomb was built, and it was directly kept secret by the magnesium military for ten years. ”

"It's a pity, Lao Feng left in his 50s......"

When Li Zheng heard this, he couldn't help but raise his hand and said, "Teacher Xie, although I rarely listen to cross talk, why do I feel like I've arrived in Deyun Club?"

"Eh, you also listen to Teacher Guo and Teacher Yu? I listen to it all night, do you have that energy to speak?"

"This ...... I don't reject it, but you said it was only for 15 minutes. ”

"It's a good time...... Look at this lump of fluid, three-dimensional, let's ...... in the X direction now."

"Then the Y direction, the Z direction......"

"The three directions together are this big equation, and this is the continuous equation description. ”

"With this, just put in some physical laws, and the rest can be introduced. ”

"For example, if you have a certain moment in time, you can use the momentum theorem. ”

"The first time, I'll take you to set one first, in fact, it's just these two styles...... The whole piece is a little bit more ......"

“…… Finally, we have to come up with this equation, right?"

"Oh, by the way, this is the Navistokes equation, you can memorize it and use it directly, it doesn't matter if you can't memorize it, it's like I can push it like this. ”

"Sometimes I don't have a rut, the equation is too TM, it's not as comfortable as pushing it out myself. ”

"In addition, you don't have to use the momentum theorem here, you can also deduce this equation by applying other physical laws that can construct the relationship between time and velocity, you can try to play with it yourself, I won't talk about it. ”

"Alright. He threw the chalk and clapped his hands, "That's the idea, now you should be able to deduce all the equations of fluid mechanics, and in some places you need to use linear algebra, so you won't learn it yourself." ”

Li Zheng: "???"

"Huh, is there anything else you don't understand?"

"Ah......" Li Zheng trembled and hung his head.

It's not a question of incomprehension.

I don't know what I need to know!

Li Zheng stubbornly asked, "For example...... Problems with the flow in the tube of viscous fluids. ”

"Isn't that just a tube and a few forces together to get it done?"

"Really...... Then I'll look at ...... slightly" Li Zheng trembled and picked up the pen.

"Well, let's be micro first, don't ask if you don't understand, just turn the book and memorize the equations, I've already taught everything I should teach here, and I can derive the whole picture from the simplest theory, which is the basic quality of physics. ”

"Really...... What about the foundation...... "Li Zheng has already begun to sweat.

After that, Xie Qifen left the small classroom and went to the laboratory.

Li Zheng had no choice but to use his thinking to speed up.

Although it is nonsense, it does provide a set of learning methods -

It's your own derivation.

Of course, at least a thorough grasp of advanced mathematics and linear algebra is required to be qualified to push.

Presumably, the wind must have been mastered a long time ago.

And every time the competition exam, it's pushed over so hard.

No, it should have started a long time ago.

Maybe that's how he pushed the whole middle school.

Or earlier, elementary school.

Even since hitting the contact number, it has been like this.

Presumably, whether it is to see the wind or solve its disputes, it is from the beginning, instinctively chose this set of ideas, and in thousands of deductions, he strengthened his brain again and again, and finally became stronger to the extent that there is no one in ten thousand.

Of course, it may be the congenital cause that is dominant, but that doesn't prevent acquired training from coming into play.

Give it a try.

Try it out in the path of these perverted geniuses.

Li Zheng went all out and embarked on a learning path that he had never walked before.

……

Half an hour later, when Xie Qifen returned to the classroom, he saw scratch paper on the ground.

", are you really pushing hard?" Xie Qifen walked up to Li Zheng in surprise, picked up a piece of scratch paper at random and looked at it, "Hmm...... That's what happened......"

Li Zheng himself has also broken away from the acceleration of thinking, his eyes are empty, and he is panting.

In the first few hours, he struggled, and more often than not, he had to use the brute-force method and apply all kinds of physical formulas in order to deduce the required equations.

It's like throwing a bunch of screws and nuts of different shapes to a blind man and screwing them together, and the blind man can only touch the outline and try one by one.

But after the 8th hour, Li Zheng gradually had vision, or rather, a sense of touch became more acute.

He can just see the shape of the nut and get a rough idea of what kind of screw is needed.

After 30 hours, he can clearly see most of the details of the nut and is completely sure what size screw is needed.

After 45 hours, he knew exactly where each screw was placed.

After 55 hours, he closed his eyes again and returned to his original state, twisting the needed screws with a single touch on the nut.

At this moment, Li Zheng stared ahead.

He didn't feel like he had learned anything.

But he confidently understands everything.

No matter what problem comes his way, he has a solution.

Feel the confidence of the enigma.

Li Zheng's entire scalp was numb.

It's a new realm!

There are no tricks to win!

At this moment, Xuzhu is not alone.

The wind is clear, Zhang Sanfeng, and Dugu are defeated, and their souls are combined at this moment!

"I ...... I understand......" Li Zheng looked at Xie Qifen and was grateful, "Thank you, Mr. Xie, thank you!!"

"......" Xie Qifen held the scratch paper and took a step back, "I...... I didn't do anything. In addition, it's okay to call me Lao Jie, crab crab is my nickname, only my mother can call it. ”

"Thank you!

"......" Xie Qifen looked at Li Zheng worriedly, picked up two pieces of scratch paper and looked at them for a while, and couldn't help sighing, "It's not easy to make so many of them...... But it can be seen that your math is average, and your methods are stupid. To tell you the truth, we still can't get it right...... I'm not sure I can continue to lecture you. ”

"It's okay, this lesson is already good. Li Zheng nodded again and again.

"Your attitude is also comfortable......" Xie Qifen put down the scratch paper, raised his hand and said, "Okay, then according to what I said before, I will come up with a final question, and if you can solve it, I will continue to talk." ”

"Please!"

"Let's have a simple fluid mechanics problem, I'll just say it once, listen well-" The corners of Xie Qifen's mouth raised, and a wicked smile swayed, "How much power can a drop of water carry?"

Li Zheng waited for a long time, and only smiled without saying anything, and then suddenly realized.

"That's it?"

"That's all. "You can set the conditions as you like, cube water droplets, spherical shapes, with or without gravity, that's all." ”

"Ahh Li Zheng opened his mouth wide, "You can ......"

"You can do anything, count it on. After rubbing Li Zheng's head, Xie Qifeng walked out of the classroom.

When he turned around and closed the door, he bumped into Lu Yang.

"Teacher Xie, the lab is almost over, let everyone go to dinner?"

"Well, lead them there. Xie Qifen leaned against the door of the classroom and waved his hand casually.

"You're not going?"

"I'll wait. ”

"Oh......" Lu Yang glanced through the door and window, and it took a lot of effort to find Li Zheng in the back row of the classroom, and then exclaimed, "Li Zheng is back?"

"Hmm. ”

"Why don't you go to the lab?"

"Isn't that unconvinced? Xie Qifen said with a smile, "Look for me by name." ”

"Ah!" Lu Yang shuddered, and then looked into the classroom.

Full of pity and pity.

Why are you so troubled, brother......

Teacher Xie's class is either a book from heaven or cross talk, isn't it good to make good use of time?

"Although this kid's aura doesn't match mine, it's quite interesting. Xie Qifen nodded to the glass and sighed, "Scientific research is all the same way, although I should prefer to return to the wind, but his way can be regarded as a road." ”

Lu Yang shuddered again, "Teacher Xie...... Are you complimenting him?"

"Don't you see that I think he's stupid?" Xie Qifen pouted, "How can I teach high school students? ”

"Whew...... That's right......" Lu Yang breathed a sigh of relief, "I'll just say that you can teach the most people like the wind." ”

"It also depends on the mood. ”

"Hee-hee-hee......"

"I didn't think you were so badly beaten before?"

"I'm leaving, I'm leaving......"

……

In the classroom, Li Zheng took advantage of the residual heat of the soaring realm to win without a move, and soon came up with an idea to solve the problem.

What is the maximum amount of charge that a drop of water can carry?

Easily, he sketched a physical image in his mind.

First, there is tension on the surface of the water droplet, causing the droplet to shrink.

The charge on the surface of the droplet expands due to repulsion.

When the repulsion force is equal to the tension force, the water droplets will not be able to maintain their form and will shatter.

At this time, the amount of charge that produces repulsive force is the maximum charge.

After figuring out the principle, Li Zheng picked up the pen and did it.

In the case of vacuum without the influence of gravity, let the water droplet be spherical, the radius is r, the density is ρ, the surface tension coefficient is σ, the carrying charge is Q, and the vacuum dielectric constant is ε.

Then, according to the "cutting analysis method" that I just learned, take a small microelement of water drops and carry out force analysis......

A slight sudden......

All at once......

No, draw a geometric diagram......

Fuck you, on curvature......

……

Appeared!

The tension is 2σr!

The style must be so handsome.

And then there's the repulsion......

Cut into cubes and slightly up.

In fluid mechanics, differentiation is heaven.

Then calculate the electric field strength......

Well...... It feels like Gauss's theorem is going to be applied here......

So in the end......

The repulsion is 12·ε(Q4πεr²)²!

Let the repulsion force and tension force be equal, and the equation is solved......

Appeared!

Q=8π√εr³σ！

To put it simply, when Li Zheng actually made it, he was already sweating profusely, and he just happened to pinch the watch and push the door back to the classroom.

He walked all the way to Li Zheng, squinted his eyes and pinched the answer sheet.

Then there was a glare.

"I'll fuck you, did you really make it?"

"Hmph, isn't it difficult......" Li Zheng straightened out his hibiscus-like hair, "Can you start telling me about your research?"

"It's not...... This ......" Xie Qifen searched for a long time but didn't find a flaw, and scratched his head irritably, "I haven't finished the question, so this is the first question." ”

"??!" Li Zheng got up angrily.

Fuck you!

"Don't worry, the second question is very simple. "Listen, second question - please use another way to solve the problem." ”

“？？？”

"Broaden your mind, half an hour. ”

Solve the dispute and just close the door and leave.

Li Zheng is not shallow.

Naturally, he could have walked away.

But in that case, wouldn't it make the ruffians happy?

No!

Untie!

Hard solution!

So, for the first time, Li Zheng went to the topic with hatred.

……

Half an hour later, Xie Qifen walked into the classroom again with his watch pinched, rubbed his stomach and walked to Li Zheng's desk.

When I picked up the scroll, I was like thunder.

"Damn!!, you stupid thing can still come up with this??"

"Hmph. Li Zheng wiped his head full of oil, and sneered strongly, "The principle of minimum action is just an ordinary undergraduate mechanics content." ”

"Third question!" Xie Qifen slapped the paper, and said with a hideous face, "Please come up with another solution." ”

"Hah...... Haha......" Li Zheng smiled miserably, looked at the sunset outside the window, and slowly took out the hidden paper from the desk, "I'm sorry, I've already thought of this layer." ”

Xie Qifeng was suddenly shocked, and the whole person's worldview trembled.

He stiffly took the answer sheet, looked at it for a while, and his hand drooped.

"This is still the first question, which forced me to take the principle of virtual work. Li Zheng smiled lightly and put away the stationery, "I know, you don't want to teach me, just say it, I'll go." ”

"You...... You ......" Xie Qifen looked at the paper all over the floor, scratching his scalp, "You beg me again...... Maybe I'll say yes......"

"No, I don't. Li Zheng picked up his schoolbag, his face was full of pride, and he was not angry.

If I learn from demons, how can I bow my head to the ruffian?

Xie Qifen's face was crooked, avoiding this righteous gaze: "You, you just say two good words and try it......"

Li Zheng frowned and said: "Smoking is harmful to health!"

“…… Heck, seeing that you care so much about the teacher's body, I will barely teach you two lessons. ”

“……”

"Let's go and eat first. Xie Qi hugged Li Zheng and walked out, "At your level, you can probably understand my research." ”

"Tell me clearly, you have to teach me. ”

"Hey, say while drinking. ”

"Drink?"

"Let's go, let's go......" Xie Qifen pushed Li Zheng, only to find that he had a piece of paper stuck to his buttocks.

He picked up the paper and looked at it, and exclaimed, "You have prepared a fourth solution???

"I'm ashamed...... Li Zheng fanned his hands and said, "This is the solution I got from the sidelines, and I can't understand it myself." ”

"If you don't understand it, you'll be right. Xie Qifeng took a picture of the paper and laughed, "The perturbation method is the method of the Nobel Prize winner in physics, help your buddy check the paper, cheap!"

"Shut up!" Li Zheng was anxious.

"Huh?" Xie Qi was stunned for a moment, then patted his head and hurriedly changed his words, "I understand, it's not a buddy, then she must have checked the paper, smart!"

"Hmm. ”

……

A few kilometers away, Lin Yujing yawned, threw away the scratch paper, and sat on the table.

This training camp seems to be quite interesting?