After that, it took Tang Zhifei a long time to calm down his emotions, and he wasted half a class out of thin air before he finally started to speak Chinese.

As for the assignment of classes, although there are still some troubles, it will also be troublesome in June and July next year.

In front of us, there are also urgent things.

That's Zhang Xiaoke's question.

"Three, one for each person, I do the original. After Zhang Xiaoke stuffed the question to Li Zheng and Jiang Qinghua, he bit off the cap of the pen, full of momentum, quite a bit of Li Zheng's early demeanor, "I want to taste a product, how demonic the question is quietly." ”

"That's right. Jiang Qinghua drew his pen coldly, "It's just for learning, not for rewards, let's take this path, right?"

Hearing this, Li Zheng felt for the first time that Jiang Qinghua was also a malleable talent.

After mixing for so long, it can be regarded as gradually getting better, not bad.

Since it was a competition, Li Zheng did not speed up the cheating, but just lowered his head and aimed at the subject as before.

Not to mention, although I have recently done a lot of chemistry problems.

But when I look at the physics questions, it's still more intimate after all.

It's like a man who has gone through the dust of the world, and in the end he still loves that bite of hometown food.

Li Zheng didn't think about it anymore and began to review the topic-

[In August 2011, after completing the lunar exploration mission, the spacecraft "Chang'e-2" launched by China flew from orbit around the moon to the Lagrange point on the Sun-Earth extension line for the first time. 】

[At this point, Chang'e-2 and the Earth are in a circular motion around the Sun synchronously.] 】

[The masses of the Sun and the Earth are known to be MS and ME, respectively, and the distance between the Sun and the Earth is R. 】

[The distance of the Lagrangian point from the Earth x satisfies the equation _______.] 】

[From this, x≈________ is solved.] (It is known that when λ<<1, (1+λ)^n≈1+nλ)

Li Zheng's first reaction after reading the question was.

It should be a competition question.

But it's not that hard.

It's completely different from the feeling of being exposed to a competition for the first time.

At that time, looking at those terrifying compounds, I was completely confused, and I could only come hard, and I could mix it up for a point.

Because a large amount of undergraduate-level chemistry knowledge is involved in chemical competition, it is a world of difference whether you have studied chemical competition or not, and you often can't even read the questions.

But Li Zheng can read this competition problem, and immediately has an idea, but he is not sure that he can solve it.

Lin Yujing has been studying secretly for so long, and everyone hasn't seen each other for another week.

Is it that simple to take out the physics questions that greet you?

Can anyone who has never seen a competition at a glance give it a try?

Or am I being too arrogant?

Maybe...... Hard?

Li Zheng was not sure, so he had to do it first.

When examining this question, the only little difficulty is probably the "Lagrange point".

Li Zheng, who is immersed in science fiction, is naturally familiar with this concept, but dwelling on it will only complicate this question.

In fact, to solve this problem, you don't need to know what the hell the "Lagrange point" is, you just need to pay attention to the key information given by the question-

1. This point is on the Sun-Earth extension line.

2. At this point, the spacecraft and the Earth are in a circular motion around the Sun synchronously.

These two points, although they are written descriptions, can be turned into geometric diagrams and mathematical formulas in an instant in the eyes of physics enthusiasts.

Since the spacecraft is on the extension line of the sun and the earth, it means that it is subject to the gravitational force of the earth and the sun in the same direction, as long as the two gravitational forces are added, it is the centripetal force of the circular motion of the spacecraft.

Since it orbits the Sun synchronously with the Earth, it means that the angular velocity ω is the same.

At the same time, between the angular velocity, the radius, and the centripetal force of the circular motion, there is F=MRω^2

Next, you only need to list these equations and solve them simultaneously, junior high school mathematics.

After three or five minutes of effort, the result of the first question came out.

The distance x from the earth at this point satisfies the equation which is –

MS/(R+X）^2+ME/X^2=MS(R+X）/R^3

The result is a bit complicated, but the idea and calculation are really simple.

Let's look at the second question.

From this, the solution is x≈_____.

This...... Isn't that just the solution to the above equation......

It's a math problem, isn't it???

Looking at the above equations, it is obvious that they are too complicated, and it is impossible to solve them with the mathematical knowledge we have now.

The reason for this lies in the (R+X)^2 on the denominator of the first column of the equation, which pulls the equation directly into the abyss.

But Li Zheng did not panic.

Just because there is a dazzling thing on the subject, as if it has been shouting "No, just look at me!

That's the hint in parentheses at the end.

(It is known that when λ<<1, (1+λ)^n≈1+nλ)

Plus the last question, also x ≈.

That's pretty obvious.

This formula needs to be used to simplify (R+X)^2.

After clarifying the idea, first change the form of (R+X)^2 to (1+λ)^n.

This becomes (1+X/R)^2R^2.

Then substitute the formula above......

Finally, the equation of the first question is ......

x≈{（ME/3MS）^1/3}R

Looking at this comfortable and beautiful answer, Li Zheng breathed a long sigh of relief, and his whole person was refreshed.

Cool.

It's still cool to do physics questions.

Finally, there is a half-math problem to taste.

Joyfully!

Even if you solve so many scary chemistry problems, the refreshing feeling is still not as good as this moderately difficult physics and math problem.

It's just that this difficulty ......

Lin Yujing, is she really taking a test?

If you want to stump Lao Tzu, at least there will be some problems......

Could it be ...... What other purpose does she have?

Is there a treasure hidden in this question?

Li Zheng couldn't help but look at the topic again

Lagrange point, Chang'e-2 spacecraft, synchronous orbit.

These terms, as well as the whole process of orbiting, are already full of physical beauty.

Just like Lin Yujing's essay called "Her Travels".

In that essay, there is no half formula.

Rather, it describes the entire physical process in a purely sensual and elegant way.

So it seems......

The solution of X is by no means the end.

The whole process of solving the problem just now is to transform these beautiful words into the above formulas.

Now that the results are out, you might as well translate the numerical results back into perceptual words.

From this point of view, the final question is no longer what x ≈.

It's Chang'e-2, how far it has to fly to dance with the eternal circumference of the earth.

Li Zheng's eyes shrank.

My heart was pounding.

NO.

No.

No..

This is not a physics problem.

It's a figurative suggestion.

I, Li Zheng, belong to the earth, which is equal to the earth.

You Lin Yujing is a woman, equal to Chang'e.

The sun is the center of eternity, the original intention and faith, equal to physics.

Convert it to death.

You, Lin Yujing, want to be with me Li Zheng and enter the arms of physics.

How far do you want to go?

Thinking of this, Li Zheng was overjoyed.

Ha!

Lao Tzu understood.

Wonderful!

is worthy of Lin Yujing, I know that you will not have such a simple question.

You're hinting at me that you want to go to the School of Physics with me, right?

If I read your hint, fill in that answer, right?

Interesting, such a question is interesting.

Li Zheng didn't think about it, pinched his fingers.

This adds an equal sign to the solution of X, and fills in the real answer -

【564】

There are 564 days left until the college entrance examination!