Yun Sangyu raised his head, a little unsure of what to say, and the corners of his mouth twitched a few times.

After that, I explained it seriously.

Unconsciously, there were more and more classmates around.

Even, even the top students in the class came over.

Yun Sangyu has already spoken it once, but unfortunately, everyone around him understands it.

I had no choice but to continue to talk about it again.

"Na, you see, Figure 17 is a vertical cross-section of a device, the virtual line AA is the intersection of the vertical section and the boundary plane of the magnetic field area, the uniform magnetic field is distributed in the right area of AA, the magnetic induction intensity B = 0.4T, and the direction is perpendicular to the paper facing outward....

In fact, it can be seen that it is necessary to analyze what the initial velocity is, which is obviously a routine problem.

However, this problem has one more pitfall than the traditional point delivery, that is, the position of the particle flying out is not obviously determined, so the initial velocity of the final flight out of the magnetic field boundary is not considered, but whether it can pass through the shutter or not. There should be a range."

Yun Sangyu's explanation can be said to be very clear, but there is no textbook for this question, so even the teacher has never talked about anything like it.

Students are inevitably a little foggy.

It's a top student, and some of them understand the tricks:

"I know, I know."

After saying excitedly, he directly took away the pen in the hand of the sitting classmate, and typed the draft on the paper.

For a while, the whole classroom was silent, everyone held their breath, and the atmosphere didn't dare to gasp.

Finally, the top students were full of scratch paper.

"I made it, Yun Sangyu, can you take a look?"

Belch.

"The front is up, the back is wrong!"

？？？

Xueba's classmates grabbed their scratch paper and looked at it, but no matter how they looked at it, they didn't see a problem.

Finally, frowning:

"Why is it wrong? I did it according to the formula, so I shouldn't make a mistake!"

Yun Sangyu pursed his lips:

"You used the right formula, but you used one less formula, so the final result was skewed."

After the words fell, he took away the pen and paper from Duffy's hand, and wrote on the paper.

The speed is faster than that of the students who just got out of school, it is more concise, and even, I have drawn pictures, which is easier to understand.

When the last word falls, stop writing instantly.

"Let's see."

The big guy can't understand this!

Especially Duffy, not a single punctuation mark was understood.

However, it did not delay the crazy worship of Dufei's roommate and tablemate.

"Sang Yu, you're too powerful!"

The classmate next to him was so anxious that he spoke:

"Yun Sangyu, let's talk about it."

Such a difficult question is very likely to be encountered in the college entrance examination.

So, everybody is very concerned.

Xueba's classmates actually understood most of them, but they also coaxed. :

"Classmate Yun, you can tell everyone about it."

Probably, this is the thirst for knowledge of the strong.

Seeing this, Yun Sangyu is not easy to refuse:

"Okay, then I'll talk about it again, the first question of this question is actually done in the figure, and the next step is to meet the shutter switch, to make it possible to get in and out, it needs to meet the time that flies before the collision and after the magnetic collision Yihao is the integer ~ times T of the shutter opening period, so the last equation of the first question is L/v0+L/0.5vO=T, substituting the above known range, solving one or several solutions, and the result is v0=100/."

Some of the surrounding classmates have already understood, after all, they have been spoken three times, and the pigs should know it.