Laboratory Building, the doorway to the back door of Physics Lab No. 1.

Shen Qi stood outside the back door, secretly observing through the glass embedded in the door.

In the physics laboratory, the walls are hung with the heads of scientists such as Newton, Kepler, Faraday, and Watt, and four big characters hang above the blackboard: the unity of knowledge and action.

The layout of the laboratory is different from that of the classroom in the teaching building, the desks are replaced by long test benches, and more than a dozen students sit behind the test benches, and some instruments and props are placed on each test bench, such as balances, vernier calipers, small balls, collision test instruments, timers, heavy hammers, etc.

But no one operated any of the experimental instruments, and the students either bent their cheeks or stared at the blackboard in front of them, with pens and paper in front of them.

A diagram of water waves was drawn on the blackboard, and chalk writing read:

"Water waves are not strictly speaking, simple transverse or longitudinal waves, because the water movement on the surface is neither perpendicular to nor parallel to the direction of wave velocity, but a superposition of both. ”

"When the water is deep enough, each point on the surface moves in a circular motion. Let the amplitude be A, the wavelength λ, and the period T. ”

"Suppose A<<λ and see a steady flow velocity in the frame of reference that follows the waveform, what are the velocities at the highest and lowest points of the wave?"

"Regardless of surface tension and frictional loss, let the density of water be ρ, the acceleration due to gravity g, and the conservation of energy should be considered, and the wavelength and period satisfy the relationship: λ=gT^2/2π. ”

Obviously, the blackboard was written on a physics problem.

The physics questions are quite verbose, and there are a lot of verbal descriptions.

The first question is not difficult, the flow velocity of the highest point and the lowest point u-v and u+v have been written on the blackboard.

The proof of the second question has not yet been written.

On one side of the blackboard, a young woman stands by the window, wearing rimless glasses, with one hand on the windowsill, looking out the window.

Shen Qi, who was secretly observing at the back door of the classroom, had a preliminary judgment that this woman should be the teacher of the competition team, and more than a dozen students, including Lin Xingyu, were team members. The female teacher made her debut physics problem for the team members, this is Lin Xingyu's so-called training?

In Shen Qi's impression, the discipline competitions of physics, chemistry, and biology should include experimental links, and what is the difference between purely doing questions and mathematics competitions?

Shen Qi continued to secretly observe, this female teacher with the competition team is not very old, it is possible between 25~35 years old, there are not many female teachers with competition, and see how strong she is.

The female teacher turned to face the team members and snapped her fingers crisply: "Who came to the stage to write the proof process of the second question?"

Lin Xingyu raised his hand.

"Okay, Lin Xingyu came to the stage to prove it. The female teacher said.

Lin Xingyu came to the stage and squeaked with chalk to write out the proof process:

1/2△mv1^2+△mg2A+p0△V=1/2△mv2^2+p0△V

Simplification:

λ=gT^2/2π

Certification

After Lin Xingyu finished writing, he looked at the female teacher.

Syllable.

The female teacher snapped her fingers again: "Smart." ”

Lin Xingyu was encouraged: "Thank you, Mr. Mu, for your affirmation. ”

Oh, Mr. Mu. Shen Qi learned the surname of the female teacher of the competition team, where did this Teacher Mu come from, why don't I have an impression? After thinking about it, in the past six months or so, I have participated in the mathematics competition at home and abroad, and I went to the Golden Autumn Camp of Yan University for training, and I have not come to the school much recently, and it is normal for there to be personnel changes in the school.

Lin Xingyu happily returned to his seat and looked at Teacher Mu with admiration, he also looked at Shen Qi with such an expression just now.

Teacher Mu looked like a learned person, she wore glasses, capable short hair, and then asked another question:

"There is a type of submarine that uses electromagnetic propulsion instead of propellers, and water flows through the propulsion pipe, regardless of the viscous resistance between the current in the pipe and the wall and water. ”

"There is a rectangular area in the pipe, which has a cross-sectional area consistent with the water inlet, and the size is a×b×c, in which a stable magnetic field B is generated by a superconducting magnet, and along the direction b, there is an electrode of the size of a×b on each of the upper and lower sides, which enters the DC power supply. ”

"Suppose the current exists only within this cuboid region and is uniform, the steady-state current magnitude is I, the seawater density is ρ1, and the seawater resistance is ρ. ”

"Suppose the submarine inlet pressure is p1, the outlet pressure is p2, the inlet area is S1 = b×c, and the outlet area is s2. ”

"1. After finding the stable flow, take the submarine as the reference system, and the flow velocity v1 and v2 of the inlet and outlet outlets. ”

"2. Calculate what is the power of the DC power supply after stable flow. ”

Mr. Mu's chalk font is vigorous and powerful, and her hand speed is fast, and she finally drew a simple diagram of the structure of a submarine thruster, and the question is finished.

"This question is adapted by me from the physics test questions of a certain college entrance examination in eastern Zhejiang Province, giving you 10 minutes to think and draft. After Mr. Mu finished speaking, he walked towards the front door of the No. 1 physics laboratory.

Shen Qi examines the problem outside the back door, this question is not difficult, that is, there are many physics knowledge points that need to be used comprehensively, electricity, electromagnetism, mechanics, energy and momentum and so on have to be made up, and there is no problem with using pure high school physics knowledge to solve this problem.

For most people, high school career is the most erudite stage of their lives, with good memory, quick response, quick thinking, and a little prince of all kinds of knowledge and a little queen of problem solving.

There are generally two trends after high school: becoming more knowledgeable or mediocre.

There are fewer of the former and more of the latter.

Youth is short and precious.

Pretend to be forced, why not take advantage of the youth.

There is no such shop in this village.

The years are unforgiving, pretending to fight for the day.

Physics problems are characterized by the idea of dominating everything, supplemented by the necessary calculations, which most branches of physics cannot compare with mathematics in terms of the amount of calculations.

However, it is difficult to make a difference in physics if you only rely on pure mathematical calculation ability and do not understand the many formula principles of physics. Ou Ye can only major in mathematics for this kind of calculation, while Shen Qi can double xiu.

In a very short period of time, Shen Qi had already calculated the first question of this submarine question, and the amount of calculation was not large.

At this time, Ms. Mu walked out of the front door of the physics laboratory, and as soon as she went out, she found that a boy outside the back door was sneaking into the laboratory.

Teacher Mu was silent, she went downstairs from the corridor near the front door, walked to the end on the second floor and went up to the third floor again, and slowly detoured back behind Shen Qi with light hands and feet.

Shen Qi, who was concentrating on the second question of the submarine question, didn't notice it, and a female teacher stood behind him.

"Is it interesting?" Teacher Mu said softly behind Shen Qi.

"It's not interesting...... Huh?" Shen Qi turned his head suddenly,, is this Teacher Mu a ghost, why is there no sound when he walks?

Teacher Mu looked at Shen Qi carefully, and said after a while: "Shen Qi, the IMO perfect score champion, why are you eavesdropping on my physics class?"

"Hello Mr. Mu, I'm just passing by. Shen Qi quickly regained his composure.