"Scales?" Xiang Xin looked at Cheng Jinzhou suspiciously: "If you are referring to the balance that was given to you last time, it is a very good one." ”

"I know, I know." Cheng Jinzhou was happy, secretly looked at the content on the face of the ring, and said with a smile: "I have some itchy hands recently, thinking about trying to make a balance by myself, but I don't understand many things......"

Xiang Xin showed a hint of disapproval, and said, "The balance is something that only a full-time star warlock can make, you just need to understand how to use it now." ”

She actually wanted to say: you don't even need to pay much attention to using it.

People who have been instilled with the greatness of astrologers since childhood have a religious fascination with astrology, a religious devotion to rank, and a religious discrimination against the weak......

Obviously feeling this kind of discrimination, Cheng Jinzhou was very uncomfortable, he was just looking for a reason, but now he was very unhappy with the other party's attitude, and said with a sour voice: "I don't think it's difficult to make a balance, if there are enough materials, it can be easily completed." ”

"I don't know anything." Xiang Xin said mercilessly: "The balance is not simply a thing that puts a crossbar in the center and then can measure the weight, the equal distance between the two sides is only the simplest requirement, it will also involve very complex mathematical ......"

"It's just a moment balance." Cheng Jinzhou shrugged his shoulders and said, "You just want to say that if you move an object a certain distance, the moment it produces should be the same, so the length of the two sides of the balance should be quite ......."

Xiang Xin's eyes were as round as her bald head.

The so-called moment balance is the principle of leverage. Archimedes said: Give me a lever, and I can pry up the earth, referring to the principle of leverage: theoretically, put a crossbar on the fulcrum, in order to balance the two parts of the fulcrum, the farther away from the fulcrum, the less labor.

Ordinary people know from common sense that as long as the length of the two ends of the crossbar is equal, the balance of the two ends can be guaranteed, but in actual use, the two sides are often unbalanced, so it is necessary to know the relationship between distance and mass - distance multiplied by mass is equal to distance multiplied by mass, which is simple to say, but not easy to prove.

The main purpose of the balance that can be used is to measure the mass, and in order to ensure its accuracy, the most common pallet balance cannot just use weights - a yard with an order of magnitude less per unit mass (Note 1) is also necessary for measurement - it uses the calculation formula of the lever principle.

was said to be the most proud, Xiang Xin's sneer also retracted, and at this moment she began to admire the master's vision again.

Cheng Jinzhou raised his eyebrows defiantly. Compared to the occult, he is considered a primary school student, but compared to these basic knowledge, the earth technology that has been tempered can completely abuse primitive people. Remembering that the newly obtained "Metrology of Mechanics" was the high-end knowledge of this era, he couldn't help but take it out and show off: "Do you know how to determine the position of balance? ”

"Comparable weight." Xiang Xin has long been familiar with these contents.

Cheng Jinzhou deliberately laughed out loud: "Superficial." ”

"What did you say?" Xiang Xin's right shoulder began to light again.

Cheng Jinzhou took a step back and said toughly: "You want to explain the problem by force? ”

Xiang Xin snorted, shook his arm, the light went out, and continued to hold his head high and said, "If you can't say something, I'll trouble you again." ”

"How hard it can be." Cheng Jinzhou pursed the corners of his mouth, picked up a wheat straw casually, held it horizontally in his hand, and said: "If you want to be completely balanced on both sides, this simplest balance is the same as nothing, no need to discuss, but if it has a certain angle of inclination." ”

Cheng Jinzhou slowly lowered the wheat straw to a 45-degree angle from the top right to the left, and said: "Now you see, the lever actually has an angle with the ground, and the moment at this time is no longer the result of length and mass, but should also add a 45-degree trigonometric value, right?" ”

Mathematics is the movement in which the old method fails, then the compensation method is designed, and finally the movement fails again in the constant pursuit of precision.

The principle of leverage is very simple, and humans in B.C. knew it, but when it was applied to trigonometric functions, it would take 1ooo years to develop.

Xiang Xin understood the disadvantages of ordinary balances, but she didn't expect that Cheng Jinzhou also knew, and she was a little dumbfounded for a while.

This is a teenager! Xiang Xin secretly estimated to himself, thinking back to when he was a teenager, was he so good......

The two looked at each other for a moment, Xiang Xin raised his chin again, and said, "I'll bring the Star Warlock materials, if it's not enough, I'll buy it again." If you make a ......"

"I won't go to Nanling." Nanling is the territory of the king of Nanling County, even if there is no Sith Sanctuary, and there are two perverted Zhao clans, how can Cheng Jinzhou be willing to find it uncomfortable.

"Although I can't change your father's decision, I will persuade him if you can really complete a high-precision balance." Xiang Xin already looked at Cheng Jinzhou with a level-headed attitude, and many of the skills in the process of making the balance were also kept secret in the Star Warlock Association, in other words, she would not actually make a high-precision balance, and the other party could say that the balance of the moment was already beyond the category of ordinary students.

Cheng Jinzhou snorted disapprovingly: "This bet is really light for you, then I'll tell you, you can do it." ”

His hands-on ability is limited compared to that of middle school students, and he is really a gentleman, and he never worries about exams.

Xiang Xin raised his head in surprise and began to doubt Cheng Jinzhou's generosity again.

"Alright, I still have something to do here, you can go out first." Cheng Jinzhou pretended to start chasing people, and he did have 1 Star Alliance point to upgrade.

The momentum was weak, and the young first-level star warlock couldn't say anything, so he obediently left the granary, and his attitude of being condescending made the boys outside look at each other.

Cheng Jinzhou squinted and smiled, and said to the ring with a very successful taste: "Let's continue." ”

"30,000 words." Customer service o1o has been waiting impatiently for a long time.

"Can't have that many words." Cheng Jinzhou wiped the sweat on his head and said, "That star warlock saw the situation in the granary just now, and it was a lot less all of a sudden, and it will be revealed." ”

30,000 words, but it costs 6o star yuan of grain, 6 tons of grain, enough as 6 cubic meters, and it is easy to be revealed.

Customer service O1O said impatiently: "13,000 words." Are you sure? ”

"That's it." Cheng Jinzhou is actually very anxious.

"My Days in Tehran" customer service O1O said coldly: "Congratulations, the level of the Star Alliance has been raised to 3." ”

Cheng Jinzhou opened the door of the granary violently, and the noon sun rushed in, and a sudden feeling of enlightenment arose.

"The age of mathematics, my time." Cheng Jinzhou thought silently in his heart and nodded silently.

……

Playing code: In the use of balances, the smallest weight can be 1 gram, if it is smaller, daily use will make it imprecise, for this reason, we use the principle of leverage, so that a large weight fixed on the balance, can show a smaller accuracy, such as o.1 gram.

……

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