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

"You think about how to go first, and I will do this question you just asked first!"

The two of them switched between making questions, doing questions and playing chess with ease.

Seeing those professors itching.

Fang Zhonggui carefully reviewed the questions.

A rod rotates around a vertical axis with a constant angular velocity w, and the angle between the rod and the axis is (90-a).

A particle of mass m can slide along a rod with moca coefficient μ.

Find the condition under which the particle remains at the same high speed during the rotation process.

After thinking for a moment, Fang Zhonggui said, "It is very useful to use the concept of huadongmoca corner!"

"If the huadongmoca coefficient is equal to the tangent of a certain angle, it is called..."

"..."

"The resultant force that presses the object against the platform must be found. If the angle between the resultant force and the normal to the plane is within the huadongmoca angle, then the moca force is large enough to prevent motion."

"The limit case is that the resultant force coincides with one arm of the moca angle."

"Student Xu Heng, for your question, when looking for the limit case where the particle moves downward on the rotating rod..."

"The force that presses the particle on the rod is the force of gravity mg and..."

As he spoke, Fang Zhonggui also wrote:

tan(a+ε)≤w2Lcosa/g≤tan(a+ε)

"Then the particle is in balance on the rotating rod."

"It can be seen from the boundary conditions that there is a higher position..."

"so……"

"..."

Finally, Fang Zhonggui gave the correct answer.

Also various drawings.

Xu Heng looked at it, "By the way, Professor Fang, but when you are reading the questions carefully, can you pay attention, your chess has not been played yet! I have been waiting so hard for you!"

Fang Zhonggui bitterly said, "Student Xu Heng, I did my best and solved the problem as quickly as possible!"

"Please respect the old and love the young!"

Xu Heng shrugged helplessly, "Okay, okay, I'll listen to you! So, you are right now, why don't you give me a question first, and then watch the chess game?"

Fang Zhonggui looked at Xu Heng and took a deep breath, "I'm famous for being able to do two things at once, but you kid, you're even better than me!!!"

"Okay, okay, I'll give you a question now!"

"This question was the one I was best at back then!"

Fang Zhonggui poses a question:

As shown in the figure, n moles of monatomic ideal gas go through a cyclic process according to the PV diagram.

该循环由等体过程（1-2）、“阶梯”过程（2-3）和等压过程（3-1）组成。

It is known that the pressure of state 2 is k times that of the initial state 1, and the volume of state 3 is k times that of the initial state 1. The "step" process consists of N steps in total, and the change of gas pressure and volume in each step are the same.

Find the heat engine efficiency for the entire cycle.

A coordinate map is also included.

Seeing this question, Xu Heng didn't open his mouth. The professor behind Fang Zhonggui gasped, "Professor Fang, you are really cruel! Isn't this the question of your third-term final exam at Peking University?"

"At that time, the entire army of third-year students in the School of Physics of Peking University was wiped out!"

Fang Zhonggui was taken aback, then turned to look at the professor, "Why are you here?"

"Aren't you afraid of becoming a public enemy?"

The professor sighed, "Hey... I don't want to disappoint them either! But they are too weak!"

"I have given several questions in a row, and everyone's attitude is either negative or unclear, which makes me lose my enthusiasm!"

"Rather than this, I might as well just relax and watch you play chess!"

Another professor also came to watch, "If someone downloads, someone will watch it!"

"You go on! You go on!"

Xu Heng looked at the two professors and couldn't help smiling.

Between Xu Heng, Fang Zhonggui and the group of professors, a tug-of-war gradually formed!

Xu Heng could see it clearly, he pressed his eyebrows slightly, and asked, "." The two professors...you...? "

These two also smiled, "We really admire you from the bottom of our hearts!"

"We admit that young people are out of blue!"

"It's not like some people!"

There is something in the words.

However, they did not question or disdain Xu Heng at all.

Xu Heng could tell from their sincere expressions.

The two professors said, "Student Xu Heng, you should be careful! Professor Fang's question is still like a devil in Peking University!"

"That's not true! Back then, all the third-year physics students were asked to hand in blank papers on this question!"

"Student Xu Heng, this question is level!"

Xu Heng smiled and read the question carefully...

after that……

He also just looked at the question carefully, and then, without thinking independently at all, he played chess with Fang Zhonggui while giving his own answer.

"According to the meaning of the question, the pressure change of each gas in the N steps is..."

"Similarly, every gas volume change..."

"The work done by the gas in a cycle is equal to the area enclosed by the closed graph line. Then the work done by the gas in this cycle is... drop the gun, eat the car, general!"

Xu Heng can solve problems and play chess correctly.

"The gas undergoes 1-2 process, which is a process of equal volume boosting. When the temperature rises, the internal energy increases. The gas absorbs heat from the outside, and the heat absorbed is..."

"..."

"General again! Professor Fang, you are gone, let's go to the next game!"

Xu Heng is so easy to handle.

It directly made the onlookers look dumbfounded.

Xu Heng still said, "In the process of 2-3: experience N times of isobaric expansion and isovolumic decompression, in which the gas absorbs heat Q2 during the isobaric expansion process, and dissipates heat during the isovolumic depressurization process, the total absorbed heat..."

"And the Clapeyron equation has..."

"..."

When the "Clapeyron equation" was mentioned, all the professors onlookers felt chills down their backs and got goosebumps all over their bodies.

They all stared wide-eyed, looking at Xu Heng as if they had seen a ghost.

Even Fang Zhonggui, who was supposed to concentrate on playing chess without distraction, opened his mouth wide and stared at Xu Heng in shock.

Xu Heng, "Uh...Professor Fang, did I say something wrong? If you are so distracted, it's easy to lose another game!"

Only then did Fang Zhonggui come back to his senses, and took a deep breath, "Hiss..."

Xu Heng looked at the two professors who were watching, "???"

These two professors, "Professor Fang's question is very dear to us! His question is a model for us to learn, and we will keep the answer in mind!"

"Student Xu Heng, have you encountered this problem before?"

"But I can't find it on the Internet at all... There is no one on the Internet... Could it be that the senior sister of the School of Physics, Peking University told you...?"

Xu Heng waved his hand, he smiled, and just wanted to say, just such a question, what about it?

But in the next second, he realized that this question was Fang Zhonggui's most proud question, and it was even called a question that Fang Zhonggui "conferred God" in the School of Physics of Peking University!

But it was a question that overwhelmed all the third-year physics students!

How could it be so simple!

Xu Heng's expression changed, and he didn't say a word.

But the two professors caught Xu Heng's expression, and they were even more shocked in their hearts!

!!!

Fang Zhonggui's scalp was even numb, he couldn't believe what he saw and heard.

It turned out that he, the person who made the problem, was the most comfortable!

However, no matter who came up with the question, the one who has no distractions is always Xu Heng!

Not only did he have no distractions, but he also easily solved a problem that stumped the third-year students of Jeonbuk University!

This can be regarded as sweeping the entire Peking University! ! !

terror!

It's so scary!

!!!

Fang Zhonggui's excitement is beyond words...

PS: Thank you [tail number 7967] [tail number 1958] for your support!

Kneel for all support!

The update will resume in two days!

I am very sorry during this time, there are few updates, the author knelt down and begged for forgiveness! .

Chapter 340

At the beginning, this question wiped out all the third-year physics students!

This is a student of Peking University School of Physics!

Even they stumbled!

Fang Zhonggui always felt that this question was well answered!

Of course, it's not because none of them answered correctly, but because both the type of questions and the way of solving them are remarkable.

For Fang Zhonggui, it was such a confident question, but in Xu Heng's hands, it didn't survive long at all, and was even answered directly by others.

Too easy!

It's too inappropriate.

Fang Zhonggui, "!!!"

The two professors watching, "!!!"

Not only these two, other professors have gradually come to watch.

One……

two……

three...

……

After that, more and more.

They frowned one by one, watching these two playing chess while posing questions to each other, they felt even more incredible in their hearts.