Xueba, I beg you to go and escort him quickly!

The class ranking hasn't changed much?

Grade rankings have improved!

Depend on!

Isn't this the collective awesomeness of the whole class?

!!!

So cool!

When Yao Ruiyi got this result, especially in physics, she was dumbfounded!

She never expected that she could improve so much.

If it's not the last one, it's lucky!

This was beyond her expectations!

She is already very satisfied.

but--

The whole class also gave her a big surprise.

It means that everyone is very strong and has made progress.

"Especially classmate Yue Pingting, this has already entered the middle grade of the class!"

"You girl, if you don't sing, you're already a blockbuster!"

"Why, being at the same table as Xu Heng, was it affected?"

Yue Pingting was taken aback, "I, have I improved? I have improved a lot? Teacher, are you talking about me?"

Yao Ruiyi, "What else? Who am I talking about?"

Yue Pingting smiled brightly!

Wow!

Yao Ruiyi looked at Yue Pingting with emotion.

When other people fall in love, their grades decline, but these two are so good, they can still go up!

hiss……

It seems that other people's grades have declined because their grades are not stable enough!

Like Xu Heng, this result is too stable!

Hard as hell!

Saying full marks is full marks!

"Okay, okay! Students who want to see the specific results can go to my office to see! Now let's look at the Chinese test paper..."

"..."

The Chinese class is over, it's physics class!

The physics teacher was on sick leave for a month and finally came back. Unexpectedly, Class 3 gave him such a big gift.

Not to mention Xu Heng's full marks, there are two students in the class who got full marks!

The moment Qin Fangming, the physics teacher, walked into the class, his eyes couldn't hold back.

"I'm going! I'm going! I'm going... I want to cry!"

"As soon as I come, you will give me such a big meeting gift!"

"You little fellows, you are too powerful!"

The class was full of joy, and everyone said in unison, "This is all thanks to Xu Heng!"

　　Qin Fangming came to Xu Heng.

Not walking, but trotting!

He ran up to Xu Heng and squatted down.

This hit!

Almost got down on one knee!

Rumbling--

This was witnessed by all the students in the class.

"Teacher Xu! Thank you! You have worked hard during this time!"

Xu Heng was confused.

Mr. Xu?

"???"

"Teacher, you are going too far!"

Qin Fangming, "No, no, I mean it sincerely! Really! What I said is true! Thank you for your hard work! Teacher Xu, thank you!"

Looking at Qin Fangming, Xu Heng didn't resist much, but just sighed, "It's good that you come!"

He can finally let go!

Qin Fangming wiped away his tears.

This feeling made the little girl cry.

"Teacher, you are exaggerating!"

Qin Fangming raised his head, "No exaggeration! No exaggeration at all! You all got the first place in your grade! Shouldn't I be moved?"

"Okay, okay! I'll read the test papers and so on when I go back today, and I'll explain them to you after I understand them myself."

"Let's go to class first!"

"I haven't been idle in the hospital during this time, so I've just taken care of preparing lessons for you!"

"Just save your energy and wait until you come back to give you a good lecture!"

"Students, open your textbooks to...!"

It's not over yet!

None of the students read the textbooks, and no one took them.

Qin Fangming was confused, with question marks all over his face.

"What's the matter, what's the matter with you?"

The physics class representative stood up slowly, "Ahem! Well, teacher... we have finished all the textbooks for this semester... Your preparation may... be useless..."

"Puff... cough cough cough cough... cough cough cough! True, true or false? Finished? Finished all? All?"

Qin Fangming's eyes widened, he couldn't believe what he heard.

Scan the whole class.

Everyone nodded seriously.

Finally, he looked at Xu Heng.

Xu Heng shrugged helplessly, "I accidentally missed the brake!"

Accidentally?

Did you finish telling me by accident?

Pooh!

Xu Heng, why don't you go to heaven!

My goodness!

You have finished telling me, what should I say?

I held back for a month!

I wanted to come back and give my classmates a good lesson when I was in the hospital bed!

Qin Fangming suddenly had no tears, and was not moved at all.

He wants to cry without tears!

"Xu Heng, I won't take you like this! You are too fierce! You are too bullying!... Hiss..."

Qin Fangming has a headache!

One head and two big.

He looked at all the students, and then at his own lesson preparation on the podium. It was so thick, and even the corresponding supporting exercises, he had carefully prepared it.

suddenly!

Full of confidence, he held back his strength, feeling that he was completely vented.

It looks like a bulging balloon with a hole pierced.

After a while, he stooped.

The smile on his face disappeared, and he felt a few years older in an instant.

The whole person is depressed.

"Teacher, teacher, are you okay?"

"Although Xu Heng has finished speaking, it doesn't mean we don't need you anymore! We still need you very much!"

Qin Fangming smiled but didn't smile.

But he quickly returned to normal, "Ahem! Alright! I accept the reality, so is there anything you don't understand? It's the content of the next course. Do you have any questions?"

No one shook their heads, let alone said a word.

Qin Fangming suddenly wanted to throw the table.

Fuck it!

His eyes twitched.

"The first few rows are fine. Don't be shy about the students behind you. If you don't understand, you can ask?"

But no one paid him any attention.

How?

Will!

Is it possible to lie?

Qin Fangming was helpless. For the first time, he felt that he was not needed. He felt that he was abandoned.

"Hey... I really want to find a mouse hole to crawl in."

Qin Fangming slowed down for a long time before he regained his composure.

Although the course is over!

But the class is still there!

When you're done, let's do the topic!

Qin Fangming began to write questions on the blackboard, and he wanted to use the questions to conquer this group of students.

"Let's do a topic!"

topic:

As shown in the figure, the writing surface of isosceles triangle with inclination angle a is fixed on the horizontal plane, and a sufficiently long light silk ribbon is laid across the top of the inclined surface on both sides of the shoe upper, and there is no friction between the ribbon and the inclined surface.

Now put a small object with mass M and m (M>m) lightly on the ribbons on both sides of the slope at the same time.

The dynamic friction coefficient between the two or five pieces and the ribbon is equal, and the maximum static friction is equal to the sliding friction.

Which of the following statements is correct when angle a takes different values?

A. The magnitude of the frictional force on two or five blocks is always equal