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

"@周梨墨, senior, just ignore them, they will make a fuss, I really don't know what Yao class is, anyway, it doesn't matter, the main thing is what are you looking for?"

Zhou Moyan suppressed the shock and mixed emotions in his heart, and said, "I want to ask you this question."

Post the topic.

Xu Heng's face darkened, "Uh... what are you kidding me, senior! Such a simple question..."

As soon as it was sent out, Xu Heng immediately withdrew it.

The group leader said, "Xu Heng is thinking about us again! Woohoo! I've seen it all!"

Feng Hechuan, "[Crying expression] Xu Heng, don't withdraw it, I've seen it all! It hurts so much!"

Luo Jianing, "Hey...too self-willed! @许健大大, I knelt down, please accept my knee!"

Wang Hanshan, "..."

Wang Quanquan, "If you withdraw it, you can pretend that nothing happened. I put it in and come out again. Is it okay?"

Fu Xidong, "@王实力, I feel like you are driving, but I have no proof!"

Everyone, "..."

Zhou Moyan, "?"

He didn't see the news of Xu Heng's withdrawal.

Xu Heng, "Ahem! Don't pay attention to these details!"

"@周梨墨, senior, you should know the motion theorem of the center of mass, right?"

Zhou Moyan, "I know this, it's just another method you mentioned."

Xu Heng was speechless.

what is it today!

Is everyone playing me like this?

Judging by the reactions of these people in the group, isn't the Tsinghua Yao class very powerful?

Why does this senior from the Yao class still ask himself such a question?

Xu Heng, "The Angular Dynamics of Particle Groups."

"..."

Xu Heng spoke roughly, but Zhou Moyan fell silent.

Seeing Xu Heng's feeling like pointing the country, Zhou Moyan blushed.

Finally, he left a sentence in the group, "It doesn't matter whether Xu Heng really knew about Yao Ban or not!"

This word appeared in the group.

Everyone didn't know what to say for a while.

group!

Suddenly it was cold!

No one dares to interrupt!

Even Senior Zhou from the Yao class said so, and everyone in the group understood a truth.

Yao Ban is nothing compared to Xu Heng.

Zhou Moyan felt Xu Heng's strength.

At least in this regard, he is ashamed of himself.

"Student Xu Heng, can I ask you, is the time to do this question really as the people in the group say, ten minutes?"

Xu Heng, "Yeah."

Answer frankly, the most deadly.

Zhou Moyan, "%￥#@￥￥......"

"Is it one way of thinking, or is it two ways of thinking?"

He didn't give up, he wanted to hear what Xu Heng said in person.

Xu Heng, "Aren't the two types the same? Senior, why are you asking this?"

Zhou Moyan, "Okay! I got it! Thank you! Thank you!"

Xu Heng, "???"

As Zhou Moyan stopped speaking, the group resumed its former excitement.

Those students at Peking University have subverted the impression of geniuses from Tsinghua Yao Class.

Including other students, are also subverted.

"Yao Ban, it turns out that it's not so untouchable... the most untouchable is Xu Hengda!"

"+1!"

"+2!"

"+3!"

"..."

"It's too scary! Now the seniors from Tsinghua University and Peking University in our group are from Wuyang Wuyang! Where do we high school students go!"

"My God! I dare not even think about it! In the past, when it was only the seniors of Peking University, they could wake up laughing from their dreams! Now with the seniors of Tsinghua University, there is no need to sleep!"

"Xu Heng's great charm is too great!"

"..."

In the group, there were more and more boasting about Xu Heng.

Xu Heng chose to ignore it.

Put away your phone and sleep on your own.

During evening self-study, Xu Heng really couldn't sleep.

After sleeping too much during the day, Xu Heng has no sleepiness now, and his face looks hopeless.

Look at Yang Kaixuan on the left, and Yue Pingting on the right.

They were all studying hard, and he was too embarrassed to disturb them.

He can only find Fang Zhonggui's "trouble".

"Hehehe...Professor Fang, don't be stingy! Give me a few questions!"

Xu Heng had a hippie smile on his face.

Fang Zhonggui vomited blood.

"This kid is entangled with me!"

Right now, Fang Zhonggui is still in the office, and the reason why he went back today without get out of class was mainly because of Xu Heng.

He also left behind two other professors in the physics department.

"Look! This kid is too much!"

"He always thinks that I have reservations about him! I'm not ashamed to confess to him!"

"Hey! What a crime..."

The other two professors also frowned.

"Professor Fang, we will support you with questions! As long as you can stump this kid, I feel that it will be more fulfilling than a physicist brought out by me!"

"I agree! After listening to Professor Fang's introduction, we also want to see his strength with our own eyes!"

Fang Zhonggui gasped, "You two, don't regret it!"

The two laughed loudly, "Professor Fang, we can't do it alone if you have covered all your questions! If we can really try his skills, it will be worth it!"

"it is good!"

Fang Zhonggui chose one of these two topics and sent it to Xu Heng.

topic:

As shown in the figure, the small dotted box is a finite network formed by 2n capacitors; the big dotted box is two identical infinite networks connected in parallel.

The structure of this infinite network is: from left to middle, the right plate of each capacitor is connected to the left plate of two capacitors, until infinity; from middle to right, the right plate of every two capacitors is connected to the left The plates are connected, even to a capacitor.

All the capacitors in the network are identical parallel-plate vacuum capacitors with a plate area of ​​S and a plate spacing of d (d<<S under the root sign).

The entire capacitor network system is connected to a battery with negligible internal resistance, and the electromotive force of the battery is constant and the magnitude is ε.Neglecting the edge effect of the capacitor, the electrostatic force constant k is known.

1. If the right plate of the capacitor marked a in the dotted line is slowly pulled to the right, the distance between the two plates becomes 2d.Find the work done by the battery and the work done by the external force in the process of pulling the plate.

2. After the distance between the two plates of capacitor a becomes 2d, place a thin metal plate with the same shape as the plate of capacitor a, the area is also S, and the charge is Q (Q>0) along the pole parallel to a Put all the plate directions into capacitor a, so that the distance between the thin metal plate and the left plate of capacitor a is x.Find the amount of charge carried by the left plate of capacitor a at this time.

· · · · · · · · · · · · · · · · · · · · · · · · · · ·????????????????

This time, both questions of the title were given!

There is no intention of hiding it!

Full of vitality!

Xu Heng's eyes lit up, "Thank you, Professor Fang!"

You have such a topic, you didn't come up with it earlier!

Really!

Xu Heng thought so, but how did he know that this is a topic that several physics professors have been pondering for a long time to come up with!

The two professors looked at Fang Zhonggui.

"Professor Fang, do you think this question is a bit..." to Xu Heng?

It's too difficult, before Fang Zhonggui could utter the three words, Fang Zhonggui interrupted them, "Both of you, I also thought like you before, but later, I feel ashamed!"

"As you can see, the problem I proposed is somewhat difficult, right? But what? He solved it! And it took so little time and two ways of solving the problem."

The two professors were silent.

After thinking about it for a while, "That's why, Professor Fang, you test him with different types of questions, right?"

Fang Zhonggui nodded.

"To be honest, Professor Fang, your solution to this question is indeed very good, but Xu Heng's second solution is the icing on the cake!"

Fang Zhonggui, "Yes!"

But the conversation changed.

Fang Zhonggui looked at the two people, "Do you think... Xu Heng also has different opinions on this question?"

.........................................

"hiss!!!"

In an instant, the two professors gasped and leaned back.

"is it possible?"

The three looked at each other in blank dismay, but they didn't dare to give an affirmative answer directly.

"This……!"

At this time, Wang Hanshan also sent a message to Fang Zhonggui, "Professor, the students in Tsinghua Yao Class are also very interested in your question!"

When Fang Zhonggui saw this sentence, he was taken aback for a moment, and then asked, "Are you sure you are not interested in Xu Heng's problem-solving ideas?"

"Student Wang, stop beating around the bush, do you want an answer?"

Wang Hanshan smirked, "Sure enough, Jiang is still old and spicy, the professor is amazing."

Fang Zhonggui, "To you, the topic is beyond the outline! It's not suitable for you."

Wang Hanshan smiled bitterly.

Anyway, they are also close to Peking University by virtue of their strength!