My IQ has been increasing year by year.

Four o'clock in the afternoon.

The administration building of the High School Affiliated to the Normal University.

A small lecture hall on the third floor.

The sunlight outside is no longer as glaring as it was at noon.

Golden rays of light streamed through the glass of the corridor, casting long shadows on the floor.

The classroom is very large.

But now, there are only six of them.

Six people.

The six top junior high school students in the province's physics competition.

Lin arrived early.

She wore an extremely loose, slightly faded printed cotton short-sleeved shirt.

Below is a pair of loose-fitting jeans that have faded slightly after washing.

She was wearing a pair of ordinary canvas shoes, with the heels casually stomped under her feet, treating them like slippers.

Her hair was simply tied into a loose ponytail with a black hair tie, with a few stray strands hanging down her forehead.

He was slumped in the middle seat of the first row, completely relaxed.

She rested her chin on her hand.

He held a black ballpoint pen in his right hand.

The pen moved back and forth between her fingers.

Looking at the leaves outside the window, I yawned listlessly.

Footsteps echoed down the corridor.

Zhou Kai walked in carrying his schoolbag.

He habitually glanced around the classroom, his gaze landing on the extremely nonchalant figure in the middle of the first row.

Zhou Kai paused for a moment, then his tense shoulders relaxed slightly.

He walked over.

"team leader."

Zhou Kai stopped two seats to the right of Lin Yi, pulled out a chair, sat down, and called out.

Upon hearing the sound, Lin stopped twirling the pen in his hand.

She turned her head lazily.

Looking at Zhou Kai, who was sitting upright and even the way he zipped up his backpack exuded a seriousness.

Lin Yi grinned and smiled.

"Hey, it's Zhou Kai."

Lin Yi rested his cheek on one hand, his tone carrying a hint of familiar teasing.

"When we got to the provincial team training camp, why did you still have that bitter, resentful look, like you were ready to go into battle at any moment?"

"Relax, there aren't any nails on the chair."

Zhou Kai took out a notebook and a pen from his schoolbag and placed them on the table.

A wry smile.

"I don't have a heart as big as yours."

Lin Yi shrugged indifferently.

"Whatever you want, you're the one who's going to get tired anyway."

She turned her head, slumped back in the chair, and started twirling her pen again.

The others also came in one after the other.

Miao Shi'an sat in the second row.

He Gui chose a seat in the corner.

The last one to come in.

It was Wang, who was talking incessantly, and Chen Zhuo walking beside him.

As Wang talked, he looked around and talked about the cafeteria food.

He originally wanted to pull Chen Zhuo to sit with him.

But Chen Zhuo walked directly to the first row and stopped to the left of Lin Yi, across the aisle.

Lin heard footsteps.

Raise your head.

Looking at Chen Zhuo, he naturally grinned, revealing a slightly casual smile.

Then, she slightly raised her chin at him as a greeting.

Chen Zhuo nodded at Lin Yi.

Then I put the pen and notebook in my hand on the table.

Wang Huashao saw Chen Zhuo sitting in the first row, and then looked at Lin Yi next to him, whose aura was impossible to ignore despite his extremely casual attire.

He didn't dare to go closer.

He then sat down in the second row, directly behind Chen Zhuo.

The classroom was quiet.

No one was whispering.

In this environment, even the most talkative Wang fell silent.

Footsteps echoed down the corridor.

Not in a hurry, not slowly.

The soles of the shoes rubbed against the ground, making a soft, rustling sound.

The door was pushed open.

An old man walked in.

He was probably in his sixties.

His hair was already gray, cut very short, and close to his scalp.

He was wearing an old, faded jacket with the zipper open, revealing an ordinary shirt underneath.

She was wearing a pair of old Beijing cloth shoes.

He was holding a chipped enamel mug in his hand.

The tea mug was large, with the words "Labor is the most glorious" printed on it in red, but the words were worn away and could not be seen clearly.

My fingers are somewhat thickened from handling chalk for many years.

Professor Wang Yourong from the Normal University.

The person in charge of this provincial physics team training camp.

He is also an extremely senior and influential figure in the domestic physics competition circle.

Professor Wang walked to the podium.

He didn't look around, nor did he offer any friendly smile.

"Bang."

He slammed the enamel mug heavily onto the lectern.

It made a dull thud.

The echoes reverberated in the empty lecture hall.

The sound was like a signal.

The six people sitting below tensed up slightly at the same time.

No roll call was given.

There was no welcoming speech to greet everyone at the provincial team training camp.

There was no interactive scene where everyone introduced themselves to each other.

Professor Wang turned around immediately.

Facing that huge blackboard.

He took a piece of white chalk from the chalk box.

Raise your wrist.

The chalk fell onto the blackboard.

The sound of chalk hitting the blackboard was like a machine gun firing in bursts.

Extremely dense, extremely crisp.

Without any pause or hesitation.

Professor Wang drew very quickly.

He didn't draw any fancy or sophisticated graphics.

He drew a very common, middle school level circuit diagram.

A dry cell battery pack, a switch, and wires connecting to a small DC motor.

A wire is wound around the shaft of the electric motor, and a wooden block is suspended below it.

This diagram is too simple.

It's so simple that even a student who's just started learning physics in the second year of junior high school can recognize it.

The drawing is finished.

Professor Wang labeled the battery with a voltage U.

An internal resistance R is marked next to the motor.

A mass m was marked next to the wooden block.

He threw the remaining chalk into the chalk box and patted the chalk dust off his hands.

He turned around.

"The problems you did in the city, at school."

Professor Wang's voice was full of energy.

"Wires have no resistance."

"An electric motor converts electrical energy into mechanical energy 100% of the time."

"Pulleys have no friction."

He picked up the blackboard eraser and tapped the electric motor on the blackboard.

"But I tell you, that's a fairy tale."

Professor Wang looked at the six junior high school students below.

"The National Junior High School Applied Physics Knowledge Competition tests the word 'application' and the real world."

"In the real world, there is no absolutely ideal model."

He unscrewed the lid of the teacup and took a sip of water.

Then he held up one finger and pointed to the picture on the blackboard.

"This electric motor is used to lift this wooden block up."

"Now, I'm going to increase the mass m of the wooden block infinitely, so much so that this electric motor can't even turn it."

"Commonly known as a stuck motor."

Professor Wang changed the subject.

"Your textbooks teach that electric power P = UI, and as long as electricity is flowing, it is doing work."

"But I'm telling you now, if the motor jams, it will start smoking and burn out if the power is applied for more than ten seconds."

He paused for a moment, looking at the boys in the front row.

Why did it burn down?

"Why doesn't it burn when it's spinning, but burns when it's stuck?"

These few words were spoken.

Zhou Kai's brows furrowed instantly.

Wang opened his mouth as if he wanted to say something, but after searching through the formulas in his junior high school textbook, he found that none of them could explain the phenomenon, so he reluctantly shut his mouth again.

"During this two-week intensive training period."

Professor Wang's voice echoed in the empty classroom.

"I'm going to smash all those fairy tales in your heads."

"I want you to learn to consider the back electromotive force generated when the electric motor rotates, and to consider how much of the energy is converted into Joule heat while being converted into mechanical energy."

Professor Wang raised his wrist and looked at an old Shanghai brand mechanical watch.

"The first diagnostic question."

"When the switch is closed, the wooden block rises at a constant speed of v."

"Don't try to apply those incomplete formulas from junior high school textbooks."

"Using the concept of conservation of energy, derive for me the actual output power of this electric motor and the algebraic expression for the upward speed v of the wooden block."

He lowered his hand.

"You have thirty minutes."

"This question is within the curriculum; it only uses the most basic knowledge of electricity and mechanics from junior high school."

"But the prerequisite is that you have to have the courage to overturn the standard answers that your teachers taught you."

"start."

The voice just fell.

The air in the classroom seemed to have been sucked out instantly.

A pure, ruthless academic attack came crashing down from the sky.

There was no shouting.

No threat.

It's just a very common phenomenon in daily life.