With that single word, "No," Jiang Yizhou stood frozen, his expression turning utterly foul.
He was now as embarrassed as he had been flashy just a moment ago.
The other students’ eyes were filled with mockery. Some of the boys who couldn’t stand his usual attitude couldn’t even hold back, snorting with laughter.
Jiang Yizhou’s face burned, but his mental fortitude was decent.
He quickly forced a relieved smile, as if his mistake had been a mere slip of the tongue.
"Oh, dear. It seems I oversimplified things."
As he spoke, he pretentiously picked up his test paper again, his brow furrowed as if he were re-deriving the solution.
But in reality, he was panicking like crazy.
Desperate for a way to save face, Jiang Yizhou’s mind raced until he finally came up with what he thought was a very reasonable explanation.
"Teacher, I think this problem might be ambiguous."
Jiang Yizhou pointed at the question.
"Since the entire chain ends up on the ground, the final pressure it exerts on the ground must be equal to its weight."
"So the process in between is just an increase from 0 to mg, which means..."
"What I said earlier, F = xgλ, or it being directly equal to mg, could also be true under certain specific conditions, right?"
Hearing this, Li Dong, sitting in the back, couldn’t help but shake his head.
’To him, Jiang Yizhou’s reasoning was as simple-minded as a paramecium’s.’
’He completely ignored the fundamental aspect of motion.’
’The chain is falling. The moment each small link hits the ground, its velocity instantly becomes zero. This drastic change in momentum produces a huge impact force.’
’To ignore this impact force and talk about static gravity... it’s an insult to Newton’s Second Law.’
Up at the front, Jiang Yang’s expression wasn’t looking too good either.
As a physics teacher, he could tolerate students failing to solve difficult problems, but he absolutely could not tolerate this kind of behavior—making up forced explanations just to save face.
Physics was a rigorous discipline. Something either is or it isn’t.
"Jiang Yizhou."
"In physics, there is no ’I think.’ The Momentum Theorem does not change because of your ’specific conditions’."
His words left Jiang Yizhou in an awkward spot, neither sitting nor standing, wishing he could find a hole to crawl into.
BRRRRING—
The life-saving school bell finally rang.
At the lectern, Jiang Yang paid the face-conscious student no more mind.
He dismissed the class.
As if granted a pardon, Jiang Yizhou collapsed into his chair.
Jiang Yang ignored him and walked toward the classroom door with his water bottle, but he stopped abruptly as he reached the entrance.
He suddenly remembered he still had a task to complete: finding someone to fill a quota.
’I don’t know what Old Yang is thinking, but I’m still counting on Li Dong to take one of the spots for the physics competition.’
At this thought, he turned and headed toward the back of the classroom.
As he passed the second row, he could still hear Jiang Yizhou explaining himself to the students around him.
"There’s definitely something wrong with this problem. The conditions must not have been complete, that’s why I misunderstood it. If they’d given all the conditions, I definitely would’ve gotten it right..."
Jiang Yang just sighed inwardly and shook his head, saying nothing.
In the back of the classroom, by the window.
Li Dong was looking down, his expression one of Concentration as he held his phone.
He was so absorbed he didn’t even notice when Jiang Yang walked up to his desk.
Seeing this, Jiang Yang was a little amused.
’He’s a Seventh Middle School student, after all. Talks a big game about entering the physics competition, but in reality, he’s just hiding in the back reading a web novel, isn’t he?’
Still, he couldn’t be bothered to intervene. As long as Li Dong agreed to sign up, that was all that mattered.
’As for reading novels in class? Let him.’
Jiang Yang even felt like teasing the kid.
He bent down, leaned close to Li Dong’s ear, and whispered.
"Li Dong, what novel are you reading? So engrossed? ’Thirty years east of the river, thirty years west of the river’?"
Li Dong jumped, startled by the sudden voice.
He shot his head up, looking at Jiang Yang in a panic.
"T-Teacher Jiang?!"
Jiang Yang smiled at him, casually glancing at the phone screen.
And then, the smile on his face froze.
On the screen was a vaguely familiar illustration—an explanation of Feynman diagrams and path integrals.
The title bar prominently displayed a line of text:
Feynman’s Lectures on Physics
Jiang Yang: "???"
He blinked hard, wondering if his eyes were going bad.
’Are novel titles this hardcore nowadays?’
’Which platinum-level author wrote this new book?’
’But that’s not right!’
’The layout doesn’t look like a novel, and all the technical terms...’
’This is the goddamn original Feynman’s Lectures on Physics!’
Jiang Yang was completely stunned.
’You’re just an ordinary high school senior. Have you even mastered the four major mechanics? And you dare to tackle Feynman?’
’Is he just trying to look cool, or is he actually reading it?’
At this point, Li Dong snapped out of it, quickly putting his phone away with an embarrassed smile.
"Um... Teacher Jiang, I... I was just browsing."
Seeing his evasive look, Jiang Yang felt an even greater sense of absurdity.
’Just browsing?’
’Browsing Feynman?’
He shook his head, thinking this might be some new form of humblebragging popular with kids these days, and decided to put the question aside for now.
"Alright, stop hiding it."
Jiang Yang waved his hand.
"I came to ask you..."
Halfway through his sentence, his gaze was suddenly drawn to the physics test paper that Li Dong had revealed while hiding his phone.
The paper happened to be open to the page with the "falling chain problem."
That in itself wasn’t strange, since they had just been going over that very paper in class.
But what Jiang Yang found incredible was...
...the answer in the solution area for that problem.
F_total = G + F_impact = (λx)g + 2λgx = 3λgx
Three times!
That’s the correct answer!
Forgetting what he was about to say, Jiang Yang reached out and picked up the test paper.
[Let the microelement be dm...]
[By the Momentum Theorem, dp = Fdt...]
[Impact force F = v(dm/dt) = λv2...]
Every step of the derivation was perfectly correct, using Calculus and the Momentum Theorem!
He even saw a small note Li Dong had written in the margin.
[If energy loss is considered, this process is a perfectly inelastic collision, and the system’s mechanical energy is not conserved.]
’Beautiful!’
Jiang Yang looked back and forth between the paper in his hands and a baffled Li Dong.
This line of reasoning was so enlightening that even he benefited from it; it was far simpler and clearer than the solutions he had found online.
He had always thought Li Dong was just an average student who was slightly better at physics, someone who could score an 80 or 90 at most, and that was on tests the school wrote themselves.
On a college entrance exam-level paper, 80 would be his absolute ceiling.
But now, it seemed he had completely misjudged him!
Being able to solve this problem with this method showed that his understanding of physical mechanisms had far surpassed the scope of high school physics.
Seeing Teacher Jiang staring at his paper without saying a word, Li Dong started to feel a little uneasy.
"Teacher Jiang? Is there a problem?"
Jiang Yang finally snapped back to his senses.
"This... You solved this?"
Li Dong, of course, knew what he was surprised about.
’It might seem like I’m showing off, but I really did solve it myself.’
So he scratched his head and said with a sincere look.
"Uh, yes, Teacher Jiang."
"I happened to be interested in Calculus recently, and when I looked at this problem, I felt that using conservation of energy wasn’t right. So I tried using the Momentum Theorem, and it just happened to work out."
"If it were a different type of problem, or a little harder, I probably wouldn’t be able to do it."
Li Dong felt he was being very modest.
After all, he had only just started Feynman’s Lectures on Physics. The massive pitfalls of quantum mechanics and other topics still lay ahead. If he encountered problems like that, he really wouldn’t be able to solve them.
But to Jiang Yang’s ears, those words took on a completely different meaning.
’Self-taught Calculus?’
’Just happened to work out?’
’Wouldn’t be able to do a different type of problem?’
’Who are you kidding?!’
’Being able to skillfully apply the Microelement Method to solve variable-mass problems? His fundamentals are terrifyingly solid!’
’This kid... he’s been hiding his talent way too well!’
At that moment, a curse popped into Jiang Yang’s mind.
’To hell with just filling a quota!’
"You... You wait here a second!"
Jiang Yang threw out the sentence, then turned and ran out of the classroom.
Li Dong stared blankly at Jiang Yang’s disappearing back.

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