Chapter 28 This candidate, why are you laughing?

"First establish a space rectangular coordinate system, and then find the position of the center of gravity of the tea cup based on the center of gravity formula."

For Xu You, who is also concerned with data competition, such an operation is too basic.

Within a minute, Xu You found the coordinates of the center of gravity of the tea cup in this coordinate system.

"As long as the center of gravity of the tea cup is at the height closest to the bench surface."

In three minutes, Xu You finished the first question.

The second question involves the force analysis of three-dimensional objects.

Xu You quickly determined the cross section and converted it into a plane force.

And based on trigonometric function relationships, moment balance and other conditions, formulas are listed one by one.

"By combining Formula 7, Formula 10, and Formula 11, you can calculate the change in final force."

In less than ten minutes, Xu You completed the entire process of the first question.

Calculated based on the 3-hour exam time, the time left for each question is about 20 minutes.

Xu You's speed gave this exam a good start.

This is the key to the difficulty of the rematch.

Many questions may be possible if candidates are given enough time.

But the difficult thing is to be able to complete the answer within the specified time.

When Xu You finished the first question, some students had just started to build the system and didn't even know how to find the height of the center of gravity.

This has a lot to do with their insufficient mathematical knowledge.

It is not easy to have time to prepare for a competition in a subject besides normal high school studies.

There are few students like Xu You who can be fully prepared for competitions in both subjects at the same time.

The second question is a relatively simple geometric optics question.

Of course, it is for Xu You.

It can be done using equi-optical path properties, which is a relatively routine question.

Questions three and four were not too difficult, but the calculation amount was slightly larger. Xu You did not have more than twenty minutes for each question.

The five and six questions are obviously starting to get longer. If you don’t look carefully, you will feel like IPhO and APhO.

For example, question 5 involves the concept of laser refrigeration. Generally, only IPhO and APhO will ask this question.

Of course, if you read the question carefully, you will find out.

Laser cooling is only briefly discussed here, and the main focus is on the Doppler effect of light and resonance absorption.

After finishing the first six questions, Xu You looked at the time and saw that there was more than an hour left.

This speed is even faster than Xu You planned.

It can give Xu You enough time to attack the last two big questions.

These last two big questions are often the two most difficult ones.

Other students, who were faster, had already completed question 5.

Slowly, I have just started to answer the third question.

Moreover, some skipped parts are not included.

Of course, there are still many students in the semi-finals who were completely defeated by the questions and chose to withdraw from the exam early.

They can only regretfully admit that the competition is not their battlefield.

They are just slightly better at ordinary high school physics, so they should just go back and prepare for the college entrance examination with peace of mind.

"Question 7 is actually not too difficult."

A dynamic problem mainly examines the force analysis of rigid bodies.

The thinking difficulty is medium, and it can only be said that the calculation amount is slightly larger.

After three small questions, Xu You listed more than twenty formulas one after another.

Although Wu Jing can use a calculator, Xu You directly calculated some simple calculations by himself.

This is also an experience summarized by Xu You.

Unless it is a particularly large number or a particularly difficult equation to solve, writing calculations may be more convenient than using a calculator.

In twenty-five minutes, Xu You completed the entire seventh question.

There are more than forty minutes left to solve the last question, which can be said to be more than enough.

The final question, a dynamic electromagnetic induction problem, requires candidates to set appropriate parameters and perform calculations.

The question itself is not very creative. The difficulty is that the process is cumbersome and the calculation amount is relatively large.

However, after thirty minutes, Xu You successfully completed it.

After solving the last data, Xu You could finally breathe a sigh of relief.

The test papers for the semi-finals were quite impressive!

It is far more challenging than the preliminaries exam.

The only drawback is that the questions seem a bit retro and routine, lacking a certain amount of creativity.

It can be seen that the teacher who set the questions probably took some previous questions, revised them, and pieced together a test paper.

If Xu You had the opportunity to write his own questions in the future, he would definitely not be so hasty.

It would be better to come up with some question types that are not even in the book, that would be interesting.

Thinking about the scene where the examinee was scolding the devil behind his back, Xu You felt an inexplicable bad taste.

"Why does this child seem to be smiling?"

The invigilator also noticed Xu You.

Among the many sad-faced candidates, Xu You seemed very special.

Not only was his expression very relaxed, but he also seemed to have thought of something happy.

With suspicion, the invigilator walked around Xu You and looked at Xu You's test paper.

I actually answered every question perfectly.

"At this level, it should be a bit better, right?"

The monitoring teacher finally understood Xu You.

If it were me, I would be able to answer a test paper of this level like this.

He must have been happy for a long time.

Of course, Xu You only relaxed his mind for a short time after answering the paper.

Immediately afterwards, he inspected it carefully again.

For such an important exam, Xu You would not hand in the paper in advance casually if he was not sure.

As soon as 12 o'clock arrived, the bell rang for the end of the exam.

Many candidates did not notice the passage of time and could only stop writing quickly and hand in the paper.

After collecting the papers, there was a cry in the examination room.

"It's over. You won't get 0 points in the rematch. I feel like I couldn't get every big question right."

"I feel like my brain has been burned out and I can't even remember what I just wrote."

"Half of the questions haven't been calculated yet, so I definitely don't have to prepare for the experimental exam, which is good."

Naturally, Xu You would not participate in such meaningless complaints, but walked straight out of the examination room.

He was still waiting to work out the answer with Hu Shucheng.

This time, Hu Shucheng did not submit the paper in advance.

I happened to bump into Xu You outside.

"Didn't you hand in the paper in advance this time?"

Seeing Hu Shucheng also in the aisle, Xu You asked with a smile.

"Don't let it go to waste this time. The theoretical and experimental points are cumulative, and every point is important. Let's go to the Golden Arches to answer the question this time!"

Because of the questions in the semi-finals, the difficulty has obviously increased.

It is simply impossible to complete the entire process clearly by just answering the question verbally.

It would be better to find a place to reconstruct the process of answering the questions.

"Okay, I'll treat you!"

"Then I'm not welcome."

In order to thank Hu Shucheng for his guidance on his experiment, Xu You naturally wanted to treat Hu Shucheng to a good meal.

"Just give me two copies of 1+1."

"Hey, please, let's eat something expensive."

Xu You was not stingy and ordered two luxurious cheese-thick beef burger set meals and added a snack.

While eating, the two of them resumed the process of answering just now.
Chapter completed!