Chapter 243

In a small classroom, the door was closed like a cloud and water, the window was opened, the platform sat, and the smoke was picked up.

This series of actions is one-in-one, and there is no cultural feeling.

This is probably the legendary learning ruffian.

Li Zheng's behavior is completely opposite to him, put the bag, put the stationery, complete the notebook, and sit upright.

To solve the trouble, I can't help but sip my mouth and sigh: "I'm going to make a national three good students for you."

"Ah? Three good students and national level? " Li Zheng is bound to be eager to try.

"Yes, all, and world class ones," he said with a laugh. "Go to Moscow to evaluate and Lenin will give awards."

"Boring." Li Zheng thought for a moment and soon found the wrong thing. "Right, you said this is a good League member?"

“…… You are It's serious. " He asked, not saying much about it, and asked, "what part of physics do you want to listen to? Except quantum mechanics

"Ah? I want to hear quantum. " Li Zheng said holding stationery and sitting in the last row of the classroom, which tastes a little bit.

"Quantum mechanics is a mass marketing organization, and those people don't know what to do." Solve its dispute resolutely hand in hand, "hurry, change one."

"Then listen to your more specialized field." Li Zheng replied.

The solution to the dispute more resolutely put hands: "also not, I do not understand what you do, I also lazy to say you understand, even if you understand, it will not be good for your future."

Li Zheng complained: "how can you tell a lesson so many things?"

"I'll tell you the eternal motive again."

"Don't don't do it..." "Then I don't learn very well in hydromechanics," Li Zheng said, scratching his head

"Normal." "The solution is a smoke nuzui," Lagrange description, Euler description, Bernoulli equation all know? "

"Yes, but not deep."

"Then I ask you, what do the three brothers have in common?"

"Well..." "They are mathematicians," Li Zheng replied, hardly thinking

"Oh, right!" To solve the problem, he pinched the smoke and jumped off the desk and walked to the blackboard. "Turn the physical law into mathematical equation, and cut the fluid into small pieces, and solve it with the calculus. This is hydrodynamics. Of course, this is only Lagrange's way, and Euler's method is more wild. To put it more, if you think about it, all physical problems can be solved by this routine. "

"Ah." Li Zheng stared at him. "This is not Return to the wind? "

"Yes, I heard of him from the counting house." He has been studying physics concepts in high school textbooks, and has been translated into mathematical thinking to solve problems. The mathematics academy has asked him to attend the problem long ago, but he just doesn't go

"Alas Don't mention him. " Li Zheng urged, "you can continue."

"Well, let's tell you the Lagrange description first." The solution to the problem is drawn on the blackboard, which is a beach of water, cut the block in differential way, and draw a series of stress schematic diagram.

"This is the physical image that is the most fundamental for fluid analysis."

"We need to use physical images as hubs to connect the mathematical world."

"Of course, top talent doesn't need this stuff. They have a translation system in their brain circuit."

"For example, von Neumann, who also did this, was made when he made atomic bombs with Fermi and Feynman. When the three brothers put together a piece of calculation, Fermi was older, and with a ruler, Feynman was young, and with computers, Feng did not use anything, so he calculated his mind. The result was always faster than the two brothers."

"Then the atomic bomb experiment was successful, and the two brothers went home after their work. As a result, when Feng nuoyman was calculating, he had finished a" Neumann stability analysis "by the way. The two directly bloomed in mathematical physics. Unfortunately, they were invented by the way when they made the atomic bomb, and were kept secret by the MgO for ten years

"Unfortunately, Feng left in his 50s..."

Li Zheng heard this, can not help but raise his hand and say: "jieteacher, although I rarely listen to the crosstalk, but why have a feeling of Deyun society?"

"Ah? Do you listen to Mr. Guo and Miss Yu? I listen to the end of the day, is it all that strong to speak? "

"This I don't reject this, just say it's 15 minutes. "

"Well, this time is not a count You see this lump of fluid, three-dimensional, we are now in the X direction of a little bit... ""

"Then y, Z..."

"Three directions are all together, and that's the big equation, and this is the description of the continuous equation."

"With this, you can put some laws of physics into it, and all the others will be able to push it out."

"For example, at a certain time, you can use momentum theorem."

"For the first time, I will take you to set one, in fact, it is just these two types And then we'll be all together... ""

“…… And finally, you have to come up with this equation, look good? ""Oh, by the way, this is the navistokes equation. If you can recite it, you can use it directly. If you can't, it doesn't matter. Just push it like I did."

"Sometimes I have no idea. There are too many equations. It's not as comfortable as pushing them out."

"In addition, we don't have to use the momentum theorem here. We can also deduce this equation by using other physical laws that can construct the relationship between time and speed. You can try to play with it when you're free, so I won't talk about it."

"All right." He threw chalk and clapped his hands. "These are the ideas. Now you should be able to deduce all the equations of fluid mechanics. Some places need to use linear algebra, so you won't learn by yourself."

Li Zheng:

"Well? What else do you not understand? "

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

It's not that you don't understand.

I don't know what I should understand!

"For example The problem of viscous fluid flow in pipes. "

"Isn't that just a pipe and a couple of forces, and then we're done?"

"Yes Then I look at it slightly... " Li Zheng picked up the pen trembling.

"Well, let's start with the details. If you don't understand, don't ask. Just turn to the book and recite the equation. I've already taught everything here. To be able to deduce a complete picture with the simplest theory is the basic quality of physics."

"Really What about the foundation... " Li Zheng has 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's bullshit, it does provide a set of learning methods to solve the disputes.

Of course, we should at least have a comprehensive grasp of advanced mathematics and linear algebra to be qualified for deduction.

Surely, guijianfeng must have mastered it for a long time.

And every time the physical competition exam, it is so hard to push it over.

No, it should have started a long time ago.

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

Or even earlier, primary school.

It's even been the case since the touch numbers.

It must be that from the beginning, instinct has chosen this way of thinking whether it is to return to the view of the wind or to solve its disputes. In the thousands of deduction, it strengthens one's brain again and again, and finally becomes stronger than one in ten thousand.

Of course, it may be congenital, but that doesn't prevent training from working.

Try it.

Try the path of these perverted geniuses.

Li Zheng started with all his strength and embarked on a learning road he had never gone through.

……

Half an hour later, when he returned to the classroom, he saw a piece of scribble paper.

"Shit, are you pushing hard?" Xie Qifen was surprised to walk to Li Zheng, picked up a piece of draft paper at random and looked at it carefully, "um That's what happened... "

Li Zheng himself, also out of the thinking speed up, eyes empty, straight breath.

In the first few hours of his life, he was struggling with this learning method. More often than not, he could only use the method of violent exhaustion and apply various physical formulas in order to calculate the equations needed.

It's like throwing a bunch of screws and nuts of different shapes to a blind man, who can screw them together. The blind man can only touch the outline and try one by one, and only by coincidence can they be aligned.

But in the eighth hour, Li Zheng gradually had vision, or touch became more acute.

He can see the shape of the nut and know what kind of screw is needed.

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

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

Fifty five hours later, he closed his eyes again and went back to his original state. With just a touch on the nut, he could easily twist the screw he needed.

At this moment, Li Zheng is staring at the front.

He didn't feel that he had learned anything.

But he was confident that he could see everything.

He has a solution to any problem.

Feeling the confidence of mystery.

Li Zheng's whole scalp was numb.

It's a new realm!

No move is better than no move!

At this moment, xuzhu is not alone.

Fengqingyang, Zhang Sanfeng and seeking defeat alone are the soul combination at this moment!

"I I understand... " Li Zheng looked at the solution of the dispute, grateful, "thank you, Mr. Xie, thank you!"

“……” Jieqifen held the manuscript paper and took a step back, "I I didn't do anything. In addition, call me Laojie. Crab is my nickname, only my mother can call it

"Thank you! Thank you“……” Xie Qifen looked at Li Zheng anxiously. He picked up two pieces of paper and looked at it for a moment. He couldn't help but sigh, "it's not easy to make so many But you can see that your math is average and your method is stupid. To be honest, we are still not on the right track I'm not sure I can continue to teach you. "

"It doesn't matter. It's a good lesson." Li Zheng nodded repeatedly.

"You are comfortable with this attitude..." To solve the dispute, he put down the paper and raised his hand and said, "OK, according to what I said before, I will come up with a final problem. If you can solve it, I will continue to talk about it."

"Please!"

"Let's just have a simple fluid mechanics problem. I'll say it once. Listen to it --" how much electricity can a drop of water carry at most? "He said

After waiting for a long time, Li Zheng just laughed and didn't say anything about his opinions.

"That's it?"

"That's it." "If you set the conditions as you like, the cube drops will do, the sphere will do, and there will be no gravity. That's it."

"Ah." Li Zheng opened his mouth wide and said, "yes..."

"Whatever you can, you can count on it." After he rubbed Li Zheng's head, he went out of the classroom.

Turning around and closing the door, I ran into Lu Yang.

"Mr. Xie, the lab is almost finished. Let's go to dinner at home?"

"Well, take them." He leaned against the door of the classroom and waved his hand casually.

"Are you not going?"

"I'll wait."

"Oh..." Lu Yang glanced at the door and window, and found Li Zheng in the back of the classroom with great effort. Then he said, "is Li Zheng back?"

"Well."

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

"I don't think so." Solution of its dispute in its mouth smoke smile way, "roll call me."

"Ah Lu Yang shivered and looked into the classroom.

Full of pity and pity.

What are you doing, brother

It's not good to make good use of your time?

"The boy's aura doesn't agree with me, but it's interesting." He sighed, lighting the glass. "Scientific research all leads to the same goal. Although I should prefer to see the wind, it's also a way."

“！” Lu Yang is a shiver again, "Xie teacher Are you praising him? "

"Don't you know I think he's stupid?" How can I teach high school students? To amuse him, he is determined to be unable to work out the problem, so as to drive him home

"Hoo That's right... " Lu Yang relaxed, "I said, you teach guijianfeng at most."

"It depends on the mood."

"Hee hee..."

"Didn't you think I deserved it before?"

"I'm going, I'm going..."

……

In the classroom, Li Zheng took advantage of the waste heat of the soaring realm, and soon came up with a solution.

How much charge can a drop of water carry?

It was easy for him to sketch out a physical picture in his mind.

First of all, there is tension on the surface of the droplet, which causes it to contract.

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

When repulsion is equal to tension, water droplets will not be able to maintain their shape and then break up.

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

After he figured out the principle, Li Zheng did it.

In the case of no effect of gravity in vacuum, let the water drop 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 "slice analysis method" just learned, take a small element on the water drop for stress analysis

A little bit

A little more

No, draw a geometry

Damn it, curvature up

……

There it is!

The tension is 2 σ r!

The formula must be right.

And then there's repulsion

Cut it up. It's tiny.

Whatever, in fluid mechanics, differential is the sky.

Then calculate the electric field strength

Well I feel that Gauss theorem is going to be applied here

So in the end

The repulsion force is 12. ε (Q4 π ε r?)!

Let the repulsion force and tension be equal, and solve the equation

There it is!

Q=8π√εr³σ！

To put it simply, when Li Zheng did it, he was already sweating. To solve the dispute, he pinched his watch and pushed the door back to the classroom.

He walked all the way to Li Zheng, squinting and pinching the answer sheet.Then there was a stare.

"I'll go to your mother's house and do it?"

"Well, isn't it very difficult..." Li Zhengli cut out the lotus like hair, "can you start to tell me about your research?"

"No This... " The solution of its dispute for a long time also did not find the flaw, fidgety scratched his head, "I did not finish the topic, this is the first question."

“？？！” Li Zheng got up in surprise and anger.

Damn it! Learn ruffian!

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

“？？？”

"Open your mind, half an hour."

So he closed the door again.

Li Zheng was very angry.

Naturally, he can leave.

But that way, isn't it exciting to learn ruffian?

No!

Solution!

Hard solution!

Therefore, Li Zheng for the first time with hatred, to the topic of the face.

……

Half an hour later, Xie Qifen came into the classroom again, kneaded his stomach and walked to Li Zheng's desk.

When I picked up the scroll, I was furious.

"Shit!! How can you come up with this

"Hum." Li Zheng wiped his forehead full of oil and said with a strong sneer, "the principle of minimum action is just the content of ordinary undergraduate mechanics."

"Third question!" The solution of its dispute a pat of paper, full of ferocious way, "please come up with a solution."

"Ha Ha ha... " Li Zheng gave a sad smile and looked out of the window at the setting sun. He slowly took out the hidden paper from his desk. "I'm sorry, I've already thought of this layer."

“？！” The solution of the dispute suddenly shocked the whole person's world outlook.

He took the answer sheet rigidly. After only one glance, his hand dropped down.

"This is the first question that forces me to study the principle of virtual work." Li Zheng chuckled and picked up his stationery. "I know you don't want to teach me. Just say I'll go."

"You You... " Jieqifen looked at the paper all over the ground, scratched his scalp and said, "please ask me again Maybe I'll promise... "

"No Li Zheng carried his schoolbag and was proud of himself.

How can I bow to learning ruffians when I learn from demons?

His face was askew and he avoided the eyes of Justice: "you, you can just say two good words and try..."

Li Zheng frowned and said, "smoking is harmful to your health."

“…… Oh, for the sake of your concern for the teacher's health, I'll teach you two classes

“……”

"Go, walk, eat first." "You can understand my research at this level," he said

"To be clear, you have to teach me."

"Hey, drink and talk."

"Drink?"

"Let's go, let's go..." When he pushed Li Zheng, he found a piece of paper on his buttocks.

He twists up the paper to see, startled: "you also prepared the fourth solution???"

"I'm sorry to say that..." Li Zheng Hufan started to say, "this is the solution I got from asking outside, and I can't understand it myself."

"You can't understand it." He took a picture of the paper and laughed, "the perturbation method is the method of Nobel Prize winner in physics. It's cheap to help your brother check the paper."

"Shut up!" Li Zheng is impatient.

"Ah?" The solution of its confusion Leng for a moment, a pat head, busy change of mouth way, "I understand, is not a friend, then she must also look up the paper, intelligent!"

"Well."

……

Several kilometers away, Lin Yujing yawned, threw away the manuscript paper and went to the table.

This training seems to be very interesting?

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