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

Wang Hanshan, "."? "

Is it a newsfeed?Or other news?

Pick it up and look, it's Xu Heng's news again.

Wang Hanshan, "!!!"

"He sent another message?"

The other two roommates smiled, "Is it not possible, give up? Come to ask for help?"

"Damn! I knew it would happen."

They leaned over to look at Wang Hanshan's cell phone.

Wang Hanshan opened the message.

Xu Heng, "Senior, is there any more? What about the second most asked question? Let's take a picture together!"

Wang Hanshan, "!!!"

The other two, "!!!"

They got up immediately, and walked out of the study room together, in the corridor, "Damn it! It's real!"

The three of them collectively felt their scalps go numb!

Their eyes widened.

The students passing by looked at these three people like idiots!

"How are you? Are you all right?"

Wang Hanshan, "No! It's fine! I'm sorry!"

They were shocked!

How long has it been, how could he figure it out!

"Impossible! Absolutely impossible!"

"If he can solve it! Today, today... I won't eat! Hungry all day!"

"This is a problem that the professor left for more than 100 students in our class!"

"It's not just a few of us who have made trouble, there are so many people in the class, even if someone can do it, it is absolutely impossible for him to be as fast as him!"

"At this time! If it was at that time, it would be when the professor wrote down the questions, and he would have answered them before get out of class ended!"

The other also nodded, "But when the class was about to end, the professor asked everyone in the class, and they all kept proving, but no one responded."

The three of Wang Hanshan looked at each other, "Hiss..."

Afterwards, Wang Hanshan immediately made a voice call to Xu Heng.

Xu Heng put on his earphones, "I'm sorry, the class is reading in the morning, so it's a bit noisy."

Wang Hanshan, "It's okay, it's okay, we can hear it! Student Xu Heng, can you share your proof ideas with us?"

Xu Heng, "This... what do you want my proof ideas for!"

This sentence is very suspicious of evasion.

(Nuoma's) This made the three of Wang Hanshan even more suspicious, "We want to hear it! See if your thinking is consistent with ours!"

When they said these words, their old faces were all red!

Xu Heng, "OK!"

"By calculating the kinetic energy and gravitational potential energy of the satellite at the departure point, it can be known that the mechanical energy of the satellite is a negative value. It can be inferred from Kepler's first law that the orbit of this satellite is an ellipse or a circle, and the center of the earth is a focus of the ellipse. or the center of a circle..."

"Since the velocity of the satellite at the departure point is perpendicular to the line connecting the center of the earth and the departure point, the departure point must be the apogee or perigee of the satellite's elliptical orbit..."

"Let the perigee, or apogee, be r at the distance from the center of the earth..."

"According to Kepler's second law, rv=(R)2w..."

"..."

“再根据机械守恒定律，可得（1/2mv2）-（GMm/r）=（1/2）m（ R）2w2-（GMm/ R）……”

"..."

"By substituting the above formula into the data, r≈1.2*10 (4th power) km can be obtained. It can be seen that the distance from the perigee to the center of the earth is greater than the radius of the earth, so it will not hit the earth."

"Question 2 According to Kepler's second law, it can be known that the area velocity of a satellite is constant..."

"..."

"According to Kepler's second law, it can be known that the satellite has the minimum angular velocity at this moment, and its angular velocity should not be smaller than this value in the following cycle...nephew"

"The satellite will complete two multi-cycle movements within 12-24 hours after the satellite falls off, and the space elevator will complete one movement cycle at the same time, so the two must meet within 12-24 hours, so that the satellite can be recovered."

after that.

Xu Heng, "Is the idea the same as yours? Also, can you give me the second question below?"

PS: Thank you [Dancing with Qing] [Yu Chen] for your support!

Kneel for all support!There will be updates later!

.

Chapter 165

"Hello? Senior? Are you there? Are you listening?"

Xu Heng frowned, "It's because my signal is bad? Why can't I hear them?"

pat!

Xu Heng hung up the phone.

The three of Wang Hanshan were dumbfounded.

They looked at each other in blank dismay, then ran back and sent the second question to Xu Heng.

Later!

Following Xu Heng's train of thought, the three of them worked together to sort it out.

They probably understood!

But some steps still need to digest.

"Ding!"

Xu Heng posted this photo in reverse, so naturally he didn't care about Wang Hanshan and the others.

Continue to read the question:

Question 2:

If the location of the sky elevator is located at 110 degrees east longitude, and a satellite departs from the elevator at a distance of Rx from the center of the earth on the space elevator (the speed of the satellite relative to the departure point on the space elevator can be regarded as zero), the orbit of the satellite after departure It can just be tangent to the equator at a certain point, so that the satellite can touch the ground at this point, and try to find the accuracy of the satellite's landing point.

Tip: This article requires numerical methods to find higher-order equations.

已知：地球质量M=6.0*10（24次方）kg，半径Re=6.4*10（6次方）m的球体；引力衡量G=6.7*10（-11次方）N*m2*kg-2；地球自转周期T=24小时；假设卫星与太空电梯脱离后只受地球引力作用。

Xu Heng got a pen and straw paper.

Yang Kaixuan was originally endorsing, but was suddenly attracted by Xu Heng's move.

For a moment, he forgot that he was still reciting the book, and looked over with his head tilted.

While looking at the question, Xu Heng murmured, "The point of tangency between the orbit of the satellite and the equator of the earth and the departure point of the satellite on the space elevator are the perigee and apogee of the orbit respectively. The total energy at the departure point is..."

Still writing.

(1/2)m(Rxw)2-(GMm/Rx)=-(GMm)/(Rx+Re)

"Simplify..."

（Rx/Re）3（1+（Rx/Re））=（2GM）/（w2Re3）

Yang Kaixuan, "???"

He was stunned!

From the previous step to the next step, isn't this a process that requires several steps to be listed on the paper?

Xu Heng, do you know how to play toilet paper?

You gave the answer straight away!

Then use a fart to play straw paper!

"Can you give some dignity to other people's performances!"

Yang Kaixuan was in a bad mood, "Hiss! Why do you always shock people?"

Xu Heng was serious and didn't pay attention to Yang Kaixuan's low-pitched complaints.

　　Xu Heng just writes his own!

It quickly follows that:

Rx≈4.7Re≈3.0*10 (4th power) km!

……

（Rx/Re）-（Rx/Re）3-（2GM）/（w2Re3）*（Rx/Re）+（2GM）/（w2Re3）=0

……

Finally, Xu Heng wrote 121 on the acting paper.

He solved it!

He figured out the answer!

Then, in order to prevent Wang Hanshan and the others from asking himself about the process, he sorted out his steps and added a lot of words that he personally thought were unnecessary.

For example: "But due to the earth's rotation, the earth has rotated through the wT/2 angle at the same time during this period", "The angular speed of the earth's rotation...", etc., such explanations.

Yang Kaixuan, "???!!"

click!

Xu Heng took a photo of the answer and sent it to Wang Hanshan.

As for Wang Hanshan, these three physics students from Peking University are still sorting out Xu Heng's first question!

"Huh, everything will be done in no time!"

Wang Hanshan was concentrating on it when his phone vibrated again.

Wang Hanshan was taken aback for a moment.

The two of them also stopped immediately, and their eyes were all focused on Wang Hanshan's mobile phone.

"What news? Push...or...?"

"hiss……"

Wang Hanshan was shaking when he picked up the phone.

I said silently in my heart, "It must not be him! It must not be him! It cannot be him! No!"

But what was displayed on the screen was a Q message reminder!

Wang Hanshan didn't dare to open it.

These two also gasped, their scalps tingling, "Look! Maybe it's not Xu Heng!"

Wang Hanshan threw the phone to them, "Look! Look!"

"it is good!"

The two held their breath, clicked on it, and said, "Ha! No, it's a news feed!"

Wang Hanshan almost cried out excitedly, "It's a good thing it's not Xu Heng, it's a good thing it's not..."

The next second!