pjbooks Chapter 22: The difference between a physicist and a physicist!
Chapter 22: The difference between a physicist and a physicist!
On the podium, Han Chuan, holding a piece of chalk, took a step back, making way for a complete area for solving the problem.
Beside him, physics teacher Fang Jianyu remained standing, leaning slightly forward, his lips unconsciously parted slightly, his face full of surprise and shock as he looked at the two solutions on the blackboard.
The left side of the blackboard is covered with densely packed derivations of Hamiltonian mechanics, the kind of material that only university physics students or competition participants would study.
Not only are the steps to solve the problem rigorous and interconnected, but the establishment of the Hamiltonian, the derivation of the canonical equation, and the solution of the motion period all demonstrate a profound understanding of physics.
On the right is a concise energy mode analysis consisting of only a few lines.
It looked simple, with a formula less than a third the length of the former, but the way of thinking that bypassed all intermediate processes and directly grasped the physical essence of the final state surprised him even more than the one on the left.
At least, this solution was something that Han Chuan, as a physics teacher, had never thought of before.
By decomposing forces and identifying energy sources, and then focusing on stable motion to establish a core proportional equation, we can then determine the stable period T.
This line of thought is frighteningly simple and clear!
Especially the entry point and turning point—not to mention this was a high school student, even his physics teacher hadn't thought of it.
This method of solution cannot be mastered by simply memorizing formulas or mechanically doing practice problems!
It requires a systematic understanding and mastery of the entire mechanics system, and a thorough understanding and mastery of the laws governing gravity, electric force, and Lorentz force.
More importantly, this requires exceptional talent and an instinctive, direct, and almost intuitive understanding of the laws of physics in order to see through the core of the problem at a glance.
It's no exaggeration to say that this intuition is the difference between a 'physicist' and a 'physicist'!
Although there is only a one-word difference between "scholar" and "expert," the actual difference between them is like heaven and earth.
Taking a deep breath, Fang Jianyu snapped out of his shock.
Instead of commenting on the solution on the blackboard, he looked at Han Chuan and asked a question.
"If the cylinder in this problem is not rigid, but instead loses energy during collisions, how would you modify your energy algorithm?"
Han Chuan was taken aback when he heard the question.
He hadn't expected Fang Jianyu to ask such a question. After thinking for a moment, he replied, "We should be able to add a dissipation term to the left side of the proportional equation, similar in form to the average power dissipation of friction."
"If the collision recovery coefficient is e, then the energy loss per cycle is proportional to (1-e²) multiplied by the kinetic energy at the time of the collision."
"Subtracting this loss rate from the drive power will reduce the stable amplitude by a power of e."
After a pause, Han Chuan thought for a moment and then added a sentence.
"However, the specific derivation depends on the boundary conditions."
"If the sidewalls are inelastic, it affects the stability of horizontal rotation; if the bottom surface is inelastic, it affects the height of vertical rebound."
"These two situations need to be handled separately; they cannot be directly applied with the same coefficient."
This time, Fang Jianyu remained completely silent.
He stared at Han Chuan for a while before saying, "The solution is excellent. You can go now."
"oh."
Han Chuan responded, put down the chalk in his hand, and stepped down from the podium.
Standing in front of the blackboard, Fang Jianyu did not erase the answers on it, but instead looked at the other students in the classroom.
"The problem-solving method that Han Chuan just demonstrated on the blackboard is not part of the college entrance examination. You don't need to learn it, and it won't be on the exam."
"However, I would like to take this opportunity to say a few words to you."
His voice wasn't loud, but it instantly silenced the entire classroom.
"You might think that what Han Chuan just wrote is like cryptic writing."
"You don't understand Hamiltonian mechanics, and you don't know what energy modes are, but that's okay. These are not things you should be learning in high school."
"But what I want to say is that truly understanding a subject is not about memorizing question types or applying formulas, but about being able to look at a question from different angles, break it down, reassemble it, and see through it."
As he spoke, he took a piece of chalk and wrote two words on the blackboard: Thinking.
"You can forget the question types, but you won't forget the thinking processes!"
"There's someone sitting next to you today who, in just over two months, went from scoring in the fifties on monthly exams to being able to solve challenging competition problems. I believe he didn't rely on mindless, repetitive practice; he truly mastered every single concept!"
"Once you've thoroughly grasped it, you too will be able to solve a problem in multiple ways, and when you see a problem, the formulas and theorems needed to solve it will automatically come to mind."
"get out of class dismissed!"
After saying that, Fang Jianyu put down the chalk, dusted off his hands, and prepared to go upstairs to find Cao Wen to snatch the person away.
If a promising talent like Han Chuan doesn't study physics or participate in physics competitions, then it's a terrible thing to do!
He's an incompetent and irresponsible physics teacher!
Even if it means a fight, he'll take Han Chuan away from him!
Just as Fang Jianyu was striding confidently outside, someone in the classroom suddenly shouted.
"Teacher Fang, it seems the bell hasn't rung yet."
Upon hearing this, Fang Jianyu paused for a moment, turned to look at the round clock hanging on the blackboard, gave an awkward laugh, and then stopped walking.
However, he did not continue lecturing. Instead, he put his lesson plan on the table, pulled out the chair next to him, and sat down.
"We have ten minutes left in class, so feel free to ask questions. Ask anything about this question."
No one raised their hand in the classroom.
Most people can't even understand the questions, let alone ask them.
Even if Han Chuan solved this problem using two different methods, it doesn't mean they can understand it.
Even the top students in the class who always score over 100 in physics exams are now staring intently at the equations on the blackboard.
Fang Jianyu wasn't in a hurry; he just sat on the podium and watched.
Although this question is beyond the scope of learning for ordinary high school students, Han Chuan's solution is extremely rare.
The second method, in particular, is a problem-solving approach that integrates a systematic understanding of the entire high school mechanics system.
It's no exaggeration to say that if the other students in Class 09 had mastered even one-tenth of this knowledge, they would have been able to cope with the college entrance examination.
Letting these students study the problem for ten minutes, even if they gain even a little bit of insight, is more worthwhile than him using the remaining 10 minutes to teach and explain the problem.
After a long while, Qu Zhiqiang, the physics class representative, finally raised his hand.
"Professor Fang, in the second solution, why is the coefficient C of the magnetic field's deflection effect on the moving charge 1/2?"
On the podium, Fang Jianyu didn't answer directly. Instead, he turned to Han Chuan, who had returned to his seat, and said with a smile.
"Han Chuan, you explain this problem."
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