Great Country Academician

After scanning the classroom, Xu Chuan settled down and began to solve the problem.

The orbital calculation of a space shuttle or a launch vehicle is a fairly basic topic in physics, but this foundation is based on universities rather than high schools.

But after mastering enough high school knowledge and a certain range of university knowledge, it is actually possible to do this type of topic.

Solution: (1) According to the orbital equation, r near = R/1+ε, r far = R/1-ε.

The total energy E and the orbital angular momentum L are conserved quantities, then L=mυnear r near=mυfar r far=mυr

or υ=L/mr

The total energy of the system is E=C/r far+L/2mr=-C/r far+L/2mr far.

where C=GMm=mrυ

GMm/r=m(υ/r) is used here.

From the expressions of ①②③ and C, we can get

R=L/mrυ

ε=√1+2EL/mrυ=√1+2EL/mrυ.

So far, the first small question is over. From the perspective of an ordinary high school student, writing out the orbital parameters R and ε can probably be put in the final question of the college entrance examination as the second small question.

But for the contestants participating in the CPHO national finals, this is just an appetizer.

After finishing the first question and the first small question, Xu Chuan continued to write and began to answer the remaining two, three, four, five, six, seven and eight small questions.

The total game time is only three hours, so hurry up.

In the examination room, the middle-aged invigilator with a thermos cup walked slowly in each classroom, inspecting each candidate's problem-solving situation while invigilating the examination.

There are two invigilators in a classroom for the national finals, one in front of the other to prevent people from cheating. At the same time, three mobile invigilators are also set up to prevent unexpected situations such as fainting of candidates.

After all, it is a national decision, and the pressure is still great, not weaker than the college entrance examination.

If you pass the exam, you can be directly admitted by famous schools, recommended in advance, and even entered the training team to represent the country and compete with candidates from other countries.

Under such high pressure, almost every year students fainted and the like happened.

As for the three mobile invigilators, they are usually pre-empted by the professors of the test group.

Just like this middle-aged man who 'floats' in various classrooms with a thermos.

This year's national final question was chosen by him and several other members of the expert group, and he is very clear about the difficulty of the question.

This year's questions are slightly more difficult, but the most difficult of the four questions is the finale question. In fact, the first question is not so difficult that most students can't solve it, but it will take more time and energy.

And this year's question group they played a little trick.

They put the penultimate question on the first question and the final question on the second question.

In this way, starting from the first question and then going to the second question, one question will be more difficult than the other, and it will give people the illusion that the next three and four questions are more difficult.

If you stick to the first and second questions, three hours is simply not enough time. In this way, there will be no time to answer the third and fourth questions, which are much easier later.

This can also be regarded as a test of the students' ability to respond immediately and lead.

If some students read the test paper as a whole and studied it first, they would definitely find this little trick.

So he is looking forward to how this year's candidates will deal with this situation.

"Which school is this kid? He's stuck on the first question, and he's still solving it so slowly. If this goes on like this, he won't have time to do the rest."

"This is Cao Wei from the No. 1 High School Attached to Master P, right? Yes, I know how to avoid the first two questions and do the latter one first."

"Hey, another one who stumbled on the first question, can't his brain be brighter?"

Unsteadily, the middle-aged invigilator man with a thermos came to the side of Xu Chuan, took a closer look, and praised in his heart:

"Hey, this guy is not bad, the third question is almost finished."

"Huh? No, this kid has finished the first three questions?"

"What the hell? Did he start with the first question? And he finished the first two questions so quickly?"

Holding the thermos cup, Qiu Chengan couldn't believe it, and leaned slightly to look at it. The answer sheet on the table was already densely written, and it seemed that he had indeed started from the first question.

"How is it possible! Which school does this little guy belong to? It's only been an hour, and the first and second questions are all done? I can't remember the wrong time, right?"

Thinking, Qiu Chengan raised his head, glanced at the big round clock hanging on the blackboard in the classroom, the hands pointed to ten o'clock, and told him brightly that it was only one hour and ten minutes before the start of the exam!

This made him swallow hard, and looked down at the name on the test paper.

On the side, Xu Chuan, who was concentrating on writing the answer, suddenly felt something approaching around him, and when he looked up, a middle-aged uncle with a thermos cup stretched out his head on his desk.

"Fuck!"

Xu Chuan was startled, he exclaimed, and quickly turned his head to one side, away from the middle-aged uncle who squatted quietly to him.

This exclamation immediately attracted the attention of all the candidates in the classroom.

Being stared at by dozens of people in the classroom, Xu Chuan looked unnatural, but he himself was taken aback.

There was someone squatting quietly beside him, and anyone who came was stunned.

Qiu Chengan looked embarrassed, but he had already seen the name on the test paper, coughed, and pretended to be serious: "Do the questions well."

After finishing speaking, he left a shadow behind everyone, and quickly slipped out of the classroom.

Xu Chuan was stunned, he didn't understand what this person was doing.

You said it was the invigilator, but you have never seen such an invigilator?

They all leaned over the table to watch other people answer the questions, what's wrong?

Shaking his head, he ignored the nervous middle-aged teacher and continued to answer questions.

After coming out of the classroom, Qiu Chengan was too embarrassed to go in again.

His behavior just now has actually been regarded as interfering with the students answering the questions, after all, it caused such a big commotion.

Sometimes when answering questions, it is often just a little bit of inspiration. When the inspiration comes, I eat three catties of bananas, and the flow is endless;

But he couldn't hold back his curiosity.

A student who can complete three major questions in one hour is still the most difficult three questions, which simply refreshed his cognition.

You must know that the second big problem was solved by him and another expert. It is so difficult that ordinary high school students can't solve it.

As the finale question, the purpose is naturally to screen out the gaps.

Now it was solved in an hour by someone, no, less than an hour, this guy solved three problems in an hour, and he even doubted his own level.

Is it too easy for the topic this time?

Qiu Cheng'an might as well be thinking about it, but he was a little puzzled.

This final question, he obviously checked it with other professors in the question group, and carefully selected it from more than a dozen questions.

They agreed that to solve this problem, even if a graduate student came, it would take at least one or two hours.

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