Super academic master: start with low adjustment scores!

Have you ever seen a dozen teachers standing outside the window during an ordinary evening self-study class?

Those eyes...

are even more aggressive?

Before this.

The students in Class 304 had never experienced this.

But today.

They felt it for real.

The top students with good grades didn't care, as they were immersed in the sea of ​​questions anyway.

But those with poor grades.

Like Fatty Wang, who was a poor student who was studying hard but was actually just doing nothing, the pressure was huge.

Many students sat upright, not daring to make any small movements, for fear of being caught by the teachers.

They were all silently saying in their hearts: "Teacher, that's enough, it's almost time to go, go to other classes to inspect!"

However...

The opposite happened.

One minute!

Two minutes!

Three minutes!

...

Ten minutes passed.

Many math teachers were still standing outside the window, pointing at someone in the class and exclaiming, with no intention of leaving.

This...

The poor students all had sad faces and were desperate.

They heard that during the afternoon math test, many Chinese teachers did not supervise the test, but went to watch a certain top student.

As a result, many students in the examination room could not withstand the pressure, collapsed one after another, and gave up the test without hesitation.

Before...

They just listened to it as a joke.

They didn't care.

But now, they can finally understand the inner feelings of those who exposed themselves as cheaters.

More than a dozen teachers stared at them outside the window.

Tsk tsk!

It's okay if there is no evil in your heart.

Once there is evil in your heart.

The pressure is not small.

Many students almost couldn't help but take out their mobile phones from their pockets and handed them over obediently.

"Teacher, I violated the school rules and brought my cell phone into the school. Please confiscate it and leave quickly."

"I can't stand it anymore. I'm about to collapse."

"Please give me a way to live!"

"Woo woo woo!"

"..."

For some students in Class 304.

This evening self-study session.

It is destined to be a nightmare.

Cutting flesh with a blunt knife.

Can't live, can't die.

But Jiangnan, as the person involved, after realizing the purpose of Cao Tianyuan and others' visit, only cursed in his heart and ignored those math teachers.

He put his cell phone in his pocket, stopped reading novels, and fell asleep on the table.

"Look! Look!"

"Look as you like. I'll just sleep."

"I just don't believe it."

"You can still cut off a piece of my flesh."

"There's a saying, let him be strong, the breeze blows over the hills, let him be arrogant, the bright moon shines on the river..."

"As long as I don't feel embarrassed, then the embarrassing thing is..."

"..."

The next day.

Wednesday.

9:00 a.m.

The third science test of the monthly exam begins.

It lasts two and a half hours.

Science test includes physics, chemistry and biology, which belong to the same paper.

Physics accounts for 110 points, chemistry accounts for 100 points, and biology accounts for 90 points, a total of 300 points.

"Ding, please get 300 points in this science test."

No surprise.

The moment before the test paper was handed out.

Jiangnan's mind sounded the system prompt again.

Like the first Chinese test and the second math test, the system asked him to get full marks in this third science test.

Haha!

Full marks?

Full marks, then full marks!

Anyway, he is already famous, earning points is important.

As soon as the test paper was in hand.

He began to answer quickly.

First is physics?

Yes!

Easy.

Then chemistry?

Yes!

Still easy.

Finally is biology?

Eh?

Isn't this too easy?

Even junior high school... ahem, elementary school students can do it, and it is basically not difficult at all.

The first part is multiple-choice questions, a total of 21 questions, Jiangnan took three seconds to answer one question, and finished all in one minute.

The second part is non-multiple-choice questions, a total of 10 questions, 4 physics questions, 4 chemistry questions, and 2 biology questions.

Biology is a free-score question.

Chemistry is also a free-score question.

As for physics, only the last question is so interesting that it is worth spending two minutes on it.

"As shown in Figure A...

M, P, and N are the three vertices of a right triangle. The angle between NM and MP is 37°. A positive point charge with a charge of Q is fixed at the midpoint of MP.

The length of the rough insulating rod MN is L=1m. The x-axis is established along the MN direction (x=0 at point M).

Now a positively charged ball (which can be regarded as a point charge) is passed through the rod and released from rest at point N. The graphs of the gravitational potential energy and electric potential energy of the ball changing with position x are shown in Figure B (a) and (b). In the figure, the electric potential energy E1=3E0/5 and E2=E0/3.

It is known thatThe charge of the ball is q=8x10^-7C, the mass is m=1.0kg, sin37°=0.6, cos37°=0.8, and the acceleration of gravity is g=10m/s^2.

(1) If the elastic force of the rod on the ball is exactly zero when the ball slides down to the horizontal coordinate x in the figure, calculate the charge Q of the positive point charge fixed at the midpoint.

(2) Calculate the electric potential energy E0 of the ball at the horizontal coordinate x.

(3) If the ball moves upward along the x-axis from point M with an initial velocity v0=4m/s, it can just move to point N and then return to point M. Calculate the kinetic energy Ekm of the ball when it returns to point M. ”

The question is a little interesting.

But it’s just a little interesting.

Jiangnan spent ten seconds scanning the question, and then answered it on the answer sheet without thinking.

As for the draft paper?

Haha!

That’s a joke.

Like the previous Chinese and mathematics, he didn’t need any draft paper at all for this comprehensive science exam.

Even for the legendary physics final question, he didn’t need to spend too much time practicing on the draft paper.

Solution…

(1) At X, according to the force analysis, we know that.

kQq/r^2=mgcos37°.

Where…

From the question, we know that…

Substituting the data, we get…

Q=6, 40x10^－5C.

(2) From the figure, we know that The electric potential energy of the ball at x is equal to E0, so we can get...

E. =mgrcos0=1, 92J.

(3) Let the work done by the ball from M to N to overcome the electric field force be W, and the process from M to N is -mgLsin0-W+(E1-E2)=0-1/2mv0^2.

Solve to get...

From the symmetry, we know...

Substitute the data and solve to get Ekm=2, ​​976J.

...

Finished in one go.

Without a pause.

Jiangnan finished the last physics question.

Wow!

Too easy.

It was effortless!

How lonely and empty it is to be invincible, alone at the top, with the cold wind blowing continuously...