Yun Sangyu raised her head and glanced, not knowing what to say, and the corner of her mouth twitched a few times.
After that, I started to explain it seriously.
Unconsciously, more and more students gathered around me.
Even the top students in the class came over.
Yun Sangyu has already said it once, but unfortunately, every student around him understands it.
I have no choice but to continue talking again.
"Now, look, Figure 17 is a vertical cross-section of a certain device. The dotted line A A is the intersection line between the vertical cross-section and the boundary surface of the magnetic field area. The uniform magnetic field is distributed in the right area of AAz, and the magnetic induction intensity B=0.4T. Orientation is perpendicular to the paper facing outward.
In fact, it can be seen that it is necessary to analyze the initial velocity. This is obviously a routine question.
However, this question has one more trap than the traditional points-giving place. That is, the position of the particle flying out is not clearly determined. Therefore, the initial velocity of the particle flying out of the magnetic field boundary is not considered, but whether it can pass through the shutter is not considered. There should be a scope."
Yun Sangyu's explanation can be said to be very clear, but this question is not in the textbook, so even the teacher has never taught anything similar.
It is inevitable that the students are a little confused.
On the other hand, the top student has some clues:
"I know, I know."
After speaking excitedly, he took the pen away from the sitting classmate's hand and started writing a draft on the paper.
For a moment, the whole classroom was silent, and everyone held their breath, not daring to take a breath.
Finally, the top student filled the draft paper with eloquent writing.
"I've made it, classmate Yun Sangyu, can you take a look at it?"
Well.
"The front is right, the back is wrong!"
???
The top student quickly grabbed his own draft paper and read it, but he couldn't see any problem.
Finally, with a frown:
"Why is it wrong at the end? I solved it according to the formula, there shouldn't be any mistakes!"
Yun Sangyu pursed her lips:
"The formula you used is correct, but you used one less formula, so the final result was skewed."
As soon as he finished speaking, he took the pen and paper from Du Fei's hand and scribbled on the paper.
It's faster and more concise than the students who just finished high school, and even drew pictures, making it easier to understand.
When the last word falls, the writing stops instantly.
"Everyone, take a look."
Even the big guys can’t understand this!
Especially Duffy, he couldn't understand a single punctuation mark.
However, it did not delay Du Fei's crazy admiration for his roommate and deskmate.
"Sang Yu, you are so awesome!"
The classmate next to me spoke anxiously:
"Classmate Yun Sangyu, please tell me."
It is very likely that you will encounter such a difficult question during the college entrance examination.
Therefore, everyone is particularly concerned about it.
The top students actually understood most of it, but they also started making noises.
"Classmate Yun, just tell everyone about it."
Probably, this is the desire of the strong to seek knowledge.
Seeing this, Yun Sangyu could no longer refuse:
"Okay, let me say it again. I have actually already done the first question in the picture. The next step is to satisfy the shutter switch. To make it able to go in and out, it needs to satisfy the pre-collision and The flight time after the magnetic collision is an integer ~ times nT of the shutter opening period, so the last equation in the first question is L/v0+L/0.5vO=nT. Substitute into the above known range and solve for a or After several solutions, the result is v0=100m/s."
Some of the students around me have already understood it. After all, it has been taught three times, so pigs should understand it.