Xueba, I beg you to go and escort him quickly!

"Professor Fang, have you brought out your best questions?"

Good at questions!

Isn't it the question that Xu Heng gave before?

Fang Zhonggui kept waving his hands.

The new onlookers thought that Fang Zhonggui was being modest and taking care of Xu Heng.

They also kept persuading Fang Zhonggui, "Professor Fang! Student Xu Heng's strength is here, so don't be humble!"

"Yes! Professor Fang! Xu Heng's strength is beyond doubt! Let's try it!"

"One mind and two purposes! Now one mind and two purposes! Xu Heng, shouldn't be a big problem, right?"

"Isn't it a big problem? Don't talk about it! The difficulty of Professor Fang's question is obvious to all! Just don't..."

"..."

While everyone was discussing, Fang Zhonggui's face sank, he was very embarrassed.

"Everyone! No matter whether you are willing or not, and whether you have the same attitude, student Xu Heng has already solved that question perfectly before."

That question has been answered!

It has been answered!

Just when everyone was shocked, Fang Zhonggui said, "You all need to help me! Come up with the questions together! Otherwise, my strength alone will not be enough! You all know what Xu Heng excels at. It is obvious to all wow!"

Speaking of this, the professors who came to watch were eager to try.

They don't play chess, they only make questions!

Especially some of the questions that were denied by the people in front of them, it is completely fine for them to come up with it now!

They never get tired of it!

"Student Xu Heng, read the question!"

So far, Xu Heng's one-mind, two-task, one-to-many situation has unfolded.

Xu Heng played chess with Fang Zhonggui with ease, while answering the questions posed by the professors.

"Student Xu Heng, look at my question!"

"Professors over there think that my question is difficult, even a bit out of class!"

Xu Heng glanced at it.

topic:

Suppose S1 and S2 are the spin operators of two non-identical particles whose spin is h/2,

（1）由非耦合态a（1）a（2），a（1）b（2），b（1）a（2）和b（1）b（2）构成他们的归一化的自旋S=S1+S2为S=1，M=0的耦合态

(2) Find (S1z-S2z)|S*M=?

（3）如H=AS1*S2+B（S1z-S2z），求该体系的能量

(4) Please give the normalized eigenstate of A=0, B≠0

Xu Heng smiled, "Professor, your question is a bit too much!"

The professor disagreed, "Is my question too much? Xu Heng, I think you should know the way to solve the problem! It is obviously a very good question, right?"

Xu Heng nodded, "Indeed! Indeed!"

But Xu Heng refused to answer in detail.

In Xu Heng's opinion, thinking is the key to such a question. When he said the thinking, the professor would no longer have any problems.

He even clapped his hands, "Okay!"

After that, another professor followed.

"Student Xu Heng, look at my question."

Given two identical balls, one is placed on a horizontal surface and the other is suspended by a thin thread.

The same heat is supplied to the two spheres, will the temperature of the two spheres tend to be the same?

Explain why! (ignoring various heat losses)

Xu Heng said bluntly, "When the sphere is heated, the volume increases. The center of gravity of the sphere on the horizontal plane rises, and a part of the heat is consumed to overcome the gravity to do work, so the remaining heat to provide the high sphere temperature is reduced."

"The opposite is true for a ball suspended by a thin wire. As a result, the temperature of the ball on a horizontal surface will be slightly lower than that of the ball suspended by the thin wire!"

"This difference is very small. For a copper ball with a radius of 10 cm, the relative difference is about 10 to the negative 7th power K..."

Xu Heng spoke concisely.

His gaze now stays on the chessboard, and the process of solving the problem comes casually.

Except for the time to read the questions, Xu Heng's full attention was on the chessboard.

"Old Fang, I'm a general again!"

Fang Zhonggui stared at the chessboard, and finally sighed again, "Hey!... I lost again! I lost again! Hiss... one more round! One more round!"

"Every time it's a little bit worse! Hey..."

It's another round!

Another new question!

Another new professor came to watch.

Xu Heng drove across the "Chu River-Han Boundary", while sharply manipulating the chessboard while reading the questions.

As shown in the figure, a school bus filled with sand with a total mass of M has an adjustable small hole under the car. When the small hole is opened, the sieve leaks out vertically from the small hole.

Assuming that the mass of the sand leaked out per second is △m, when the school bus starts to move from rest on the level ground under the action of the water balance force F, the sand also starts to leak out from the small air at the same time.

If the friction of the school bus is negligible, try to prove from the law of motion that the speed and acceleration of the school bus at time t are v=(F/△m)ln(M/(M-△mt), a=F /(M-△mt).

Xu Heng smiled and directly proved: "Suppose the mass of the car at time t is m(t)=Mt△m, the speed of the school bus is v(t), and the mass of the car at time t+dt is m(t+dt)=m( t)-dm..."

"Then the speed of the school bus is v(t+dt)..."

"By the momentum theorem..."

"..."

Without any suspense, Xu Heng gave the perfect answer again.

"Crash..."

The applause continued.

Xu Heng fully utilized his single-mindedness and double-tasking, and the professors who came to watch were all in awe.

Even the professor, who had doubts about Xu Heng in his heart, had nothing to do at this moment.

They also began to indulge in chess and help Fang Zhonggui!

After all, Xu Heng can't be troubled by the topic, so he can only kill Xu Heng's prestige in chess!

However, they are always the ones who are abused.

Everyone, "%￥@￥%%￥#..."

This is the first day down.

Everyone was very depressed.

The professors who were watching Xu Heng were frustrated that there were so many of them, and they all lost to Xu Heng!

The professors who did not watch Xu Heng were frustrated by Xu Heng and the group of professors.

"He De He Neng! This Xu Heng He De He Neng! So many people flock to him!"

Some professors get angrier the more they think about it!

Straight into the dead end!

"Quit! I quit! I quit!"

"I won't participate! I won't participate!"

"Doesn't this Xu Heng think he is very capable?"

"Okay! It depends on what he is capable of!"

"I'd like to see, he's the only one, how does he get the test paper for the postgraduate entrance examination!"

"This is not difficult or difficult! This is a matter of the face of the entire Peking University!"

"%￥#￥%..."

This professor, Barabara, said a lot, but when he came back to his senses, he realized that he was the one who was alone!

It turned out that he was the clown!

dinner time.

Many professors sat around Xu Heng.

"Student Xu Heng, tell me how you came up with the idea of ​​using this method to turn defeat into victory!"

"Obviously in that situation, you already lacked a cart and a horse, yet you dare to exchange with Professor Fang!"

Xu Heng smiled, chatting and laughing with everyone.

He was invited!

What happened to Xu Heng in the production team?

On the contrary, he played chess by himself, and won a group of people's hearts by playing chess!

Who made him play chess well!

What hobbies do old people have?

Playing chess in the park is an indispensable and important activity!

Xu Heng's chess skills are amazing!

Naturally favored.

One of the professors couldn't help asking, "Student Xu Heng, do you have a girlfriend? I'll introduce my granddaughter to you! She is so beautiful! Really..."

As soon as this remark came out, the professors went on and on.

"Student Xu Heng, my eldest niece!"

"Student Xu Heng, I am always a girl! I..."

"Student Xu Heng, my granddaughter, I will push WeChat to you later!"

"..."

Xu Heng ran away quickly!

I went back to the place where I lived with Fang Zhonggui.

Only then did the ears fall clean.

Xu Heng looked at Fang Zhonggui, "Professor Fang, you don't have any granddaughters, daughters, nieces or anything like that!"

Fang Zhonggui smiled, "No! Don't worry! I'm not them!"

Xu Heng, "Phew... I'm relieved!"

Fang Zhonggui, "But I have a niece!"

Xu Heng bent over instantly, "Puff——"

"Professor Fang, you are going too far! I am not yet an adult!"

Fang Zhonggui, "Hahaha... Xu Heng, don't get excited! Don't get excited! I'm just kidding! I'm just kidding!"

Xu Heng, "Hiss...!"

Because it is closed!

So they can only move within a certain area.

Fang Zhonggui, "That's it for today! Tomorrow, student Xu Heng, do you still plan to continue playing chess with me? Or do you want to play something else?"