Zhang Bin said these words not to get praise from an old craftsman, but to lead to the following words: "If you want to improve the accuracy and facilitate adjustment, you can't use more than a dozen people to pull at the same time." ”

The old craftsman was puzzled: "But no one has such great strength, we have tried with a strong ox, but the ox is easy to panic on the battlefield, sometimes the pulling process is slow, sometimes it is indiscriminate, and it is difficult to throw stone projectiles." ”

Zhang Bin shook his head and said: "Don't use these dozen people to pull at the same time, and don't use uncontrollable livestock, but tie a heavy object, and then modify it here, and adjust the length of this throwing rod, you can adjust it now and try it." ”

As Zhang Bin spoke, he saw that the old craftsman was a little dazed on his face, knowing that the old craftsman might be experienced, but he didn't understand the principle of force conversion at all, so he squatted down and directly took a stick and drew a sketch, and no longer explained, but ordered directly.

Although the old craftsman disagreed in his heart, he even secretly slandered: "This young prisoner is a lot of things, what is the use of this kind of transformation." ”

Although he was slandered in his heart, the old craftsman immediately led people to start adjusting the stone thrower in front of him, just because he didn't understand the principle, and the adjustment process could only be commanded by Zhang Bin beside him, and it involved the problem of force distance and weight mass, which also needed to be calculated.

"Forget it, a few of you craftsmen are here, I'd better let you understand the basic principles first, otherwise I won't have time to give you guidance all the time in the future." Zhang Bin looked helpless.

After seven craftsmen came around, Zhang Bin thought for a while and said, "You've all seen the scale rod, right?" ”

"Hui officials, villains, etc. have all seen the scale pole." The seven craftsmen nodded hurriedly.

Seeing that the seven students listened to the lecture with a good attitude and were very serious, Zhang Bin continued: "Do you know why a wooden pole has a rope hanging from one end, and with a weighing stone, you can weigh the other thing? ”

The seven craftsmen shook their heads without hesitation and said, "The villain doesn't know. ”

Zhang Bin patiently explained: "The principle of the rod scale is to make the stone and the stone rope move on the scale rod to maintain balance according to the weight of the weighed object when weighing. According to the star point on the weighing rod corresponding to the balancing rope, the mass indication value of the weighed object can be read. There's a formula for that, and I'll tell you about it. ”

“……… The distance between the weight of the weighing stone and the scale for each additional pound of weight is multiplied by the distance between the lifting button and the hanging point of the weighing pan. ”

"Hmm...... You get it, right? Zhang Bin wiped the sweat from his forehead on a cold day.

"The official said it very clearly, I will understand it." The seven craftsmen suddenly realized, and when they looked at Zhang Bin again, their eyes were already very different, and the disapproval in their hearts disappeared a little.

Zhang Bin secretly breathed a sigh of relief and said, "Just listen to it, I'll give you another example, you should all know crowbars!" ”

"Yes, yes!" Seven craftsmen responded one after another, and the classroom atmosphere was very lively.

"Then do you know why with the strength of one person, with a stick and a stepping stone weighing a few catties, you can pry up a thousand catties of boulder?"

The seven craftsmen shook their heads again and again, and the old craftsman who took the lead frowned again when he saw Zhang Bin's brows, worried about the angry Zhang Bin, and hurriedly added: "We know this matter, but I don't know the principle." ”

Zhang Bin patted his forehead, sighed secretly, and said: "This principle is called the lever principle, and there is also a formula in it, you listen to it now, keep this formula in mind, and then you will use this formula to calculate the length of the stone throwing rod and the weight of the weight at the other end......"

Zhang Bin was patient, and used the wooden stick he picked up before to draw a schematic diagram of mechanics on the ground, and at the same time explained the most basic lever principles and formulas in mechanics to the seven craftsmen one by one.

Fortunately, although these seven craftsmen do not know these principles, but the utensils related to these principles are often built, which belongs to the situation of knowing what is true and not knowing why, at this time it is not too difficult to understand the principles of these formulas, Zhang Bin repeatedly talked about it for the third time, and there are already four craftsmen who have figured it out.

Zhang Bin finally asked people to find a pen, wrote out the formula of the force arm and force in Chinese, wiped a handful of sweat, and said: "Okay, the principle is such a principle, I understand the principle, but you are proficient in the specific build, now combined with the principle I said, adjust and modify, calculate several more times according to this formula, and be sure to calculate it correctly, so that the adjustment accuracy of the stone thrower created is very convenient and clear." ”

A group of craftsmen looked at Zhang Bin at this time with great admiration, and the old craftsman said respectfully: "Rest assured, it took more than two hours for the officials to let me understand the principle. ”

When Zhang Bin heard this, he finally breathed a sigh of relief, and said: "After this new type of stone thrower is built, if there is no accident, it will definitely make contributions on the battlefield, and after returning to Tokyo City, I will definitely ask you for credit." ”

When the seven craftsmen heard this, they immediately perked up and said happily: "Rest assured, the officials will do our best." ”

………

………

Sent away seven craftsmen to build a new type of stone throwing machine, Zhang Bin turned his head and saw Li Siwa and Zhimuqiu and other guards with blank expressions, and couldn't help asking: "I said so much just now, did you understand something?" ”

Li Siwa, Zhemuqiu and the others shook their heads in unison, looking confused, Zhang Bin sighed, turned his head and glanced at the seven craftsmen who had already started to work, and suddenly found that the seven craftsmen were smart people in science and engineering.

However, Orimu Qiu hesitated slightly, and said cautiously: "The prison army has studied the art of Gewu very deeply. ”

Zhang Bin's eyes lit up, and he asked with some expectation: "Mu Qiu knows the art of Gewu. ”

Orimuqiu scratched his head, and said with some embarrassment: "Our Zhe family has also had to read and write since I was a child, but I can't read, I just remember the art of Gewu, and I don't know any more." ”

Zhang Bin patted Zhimuqiu's shoulder, and said earnestly: "Your specialty is not in this area, if you don't know, you don't know, when you return to Tokyo City, I will build you in an all-round way, I hope you won't let me down at that time, as long as you can persevere, I will give you a brand new army, let you take them to the battlefield......"

After speaking, Zhang Bin left, leaving Zhimuqiu with a dazed face and muttering: "Build a ...... in all directions"

"Build and build, as long as you can run rampant on the battlefield." Orimuqiu was born in a family of generals since he was a child, and grew up listening to the stories of his ancestors galloping on the battlefield, and his biggest dream in his heart is to become an invincible general.

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