Short video spoiler history: The beginning of modern warfare

Chapter 133 The First Cosmic Velocity
Jinling City, Hexing Tea and Snack Shop.

Seeing that the day for the skylight to be opened had arrived again, Shopkeeper Wan greeted the guests and sighed in his heart. Three months had passed in a flash, and it seemed that the 'cooling time' of the skylight had been changed again. If his prediction was correct, the skylight should be lit today.

A lot of things happened in Jinling City during these three months. First, the cables and wires had been basically installed, and his shop had also been connected to an electric wire. Now the shop had been remodeled like the restaurants of later generations, with various 'lanterns' decorating small light bulbs. The light became softer after passing through the lanterns embroidered with various elegant patterns, and it looked quite unique.

At the same time, he ordered someone to install a large fan on the ceiling, which would provide cool breeze while not hindering diners from entering and exiting. Therefore, many diners would invite three or five friends to come here to kill boredom, chat and laugh together, and cool off, and they would sit here for an entire afternoon.

As for why we don’t use standing fans, it’s because many children in the city are naughty and scratch their hands, so they go to the electrical appliance store to complain.

The electrical appliance store was also very single. Although it promised that the fans produced in the future would have a protective cover and the price would increase accordingly, it would not be responsible for the previous accident. Considering the safety issue, after repeated consideration, I decided to choose this large ceiling fan.

The second is that Marquis Zhongshan, Marquis Yingchuan, and Marquis Deqing pacified Sichuan. It is said that muskets and artillery played a great role in the pacification of Sichuan. Your Majesty was very pleased and rewarded the soldiers greatly.

There was also a rumor from the palace, which was not sure whether it was true or not, that the first telephone was born in the palace. Manager Wan didn't know whether it was true or not, but he guessed that it was not much different, because many electrical appliance stores gradually made it. The court had so many skilled craftsmen in the Ministry of Industry, and they knew the structure of the telephone, so making a telephone was not a problem.

However, the electronics store's telephone was heavily advertised and had created enough hype. He went to see it that day and found the sound was a bit distorted, and sometimes there was a "crackling" noise, similar to the phonographs sold before. The shop assistant explained the reason in a lot of ways, and in summary it was that the vibration could not be restored.

Apart from these two points, there are no other shortcomings. Everyone can accept them.

However, some people also asked why there was no reminder function when someone called. This really stumped the electrical appliance store.

According to Tianmu, this telephone must be equipped with a switch. The imperial court has issued an order prohibiting the private laying of telephone lines and switches. In the past few months, telephone lines have been laid densely. They are small and much thinner than ordinary electrical wires.

In addition, the imperial court also stipulated the specifications of telephone connectors. This was a lesson learned from electrical wires, because the specifications of many electrical appliances' access plugs were privately set and there were basically no duplicates, which caused considerable trouble.

The meaning is very clear. The imperial court does not involve the production and sale of various electrical appliances such as telephones and light bulbs, but it must strictly control electrical wires, telephone lines, switches, power stations, etc., and almost no one objects to this.

Everyone is busy making electrical appliances, so who has time to care about you? Besides, this area is very troublesome in terms of input-output and subsequent maintenance, and no one wants to cause trouble.

Maybe in a few months, the telephone lines will be laid, and Manager Wan is considering whether to buy a telephone. Maybe then diners at home can just call and the store will be able to provide delivery service.

Hmm. Maybe I can start some lunch and dinner business?

Just as I was thinking about it, the shop suddenly became quiet. It turned out that the skylight had lit up on time.

[I can’t stop laughing. Yesterday, Boeing launched a manned spacecraft carrying astronauts to the space station. Despite three helium leaks, it was launched resolutely into space.]

[Shortly after launching into space, the spacecraft’s RCS failure caused it to be unable to automatically dock with the space station]

[It can only be done near the space station, and finally both parties can only carry out difficult docking under manual control]

[The docking was completed early this morning. With aerospace technology becoming more and more advanced, Boeing's operation is really humorous.]

[We know that the International Space Station was built in 1993. At that time, it was said to be jointly built by 15 countries. In fact, the United States and the Big Goose contributed the most and were responsible for the shuttle. Only this matter had some gold content. After 2011, the shuttle gradually fell on the Big Goose.]

[After they sanctioned Big Goose in 2014, Big Goose was unhappy and raised the ticket price from the original 2000 million dollars to the current 8100 million dollars. So in 2014 NASA also had a plan, which was to sign a contract with Boeing to outsource this part of the business to Boeing. It was originally planned to deliver and operate in 2017.]

[I didn’t expect Boeing to be so cunning. When the delivery date came, they kept postponing it because of bad weather or this or that problem. After finally launching, such a serious accident happened.]

[But don't worry, everyone. In addition to taking two people with them, they also brought more than 300 kilograms of food. They won't starve to death in the short term.]

Hexing Tea and Snack Shop.

The store was quiet at first, then everyone burst into laughter. No one knew why, but it just felt so funny.

"Is this a modern version of a cool novel?" A man walked in with a big laugh and said, pulling the clothes on his chest to fan himself back and forth, and walked to the corner of the fan where no one was sitting, "Boss, the old rules."

"Okay." Shopkeeper Wan responded with a smile. He knew that the word "shuangwen" was actually another way of saying this kind of revenge and relief.

"There are only two space stations, and one of them was built independently by later generations. Its value is self-evident."

"No, in my opinion, the goose can take advantage of this opportunity to make a fortune again."

"It's over. He's happy again."

Many people were jealous. Three cents could buy a pound of snow-white rice, and more than ten cents a pound of pork. 8100 million, even without considering the conversion ratio, was a huge sum of money when converted into commodity prices.

If you multiply it by 6, you will definitely make a profit.

Because of the comparison of prices, everyone realized how much this thing costs. This is the round-trip ticket. What about the round-trip "car" and the space station in the sky? Even if a bunch of people bend their toes and pull out all their hair, they still can't figure it out.

[Speaking of the space station, let me share with you its operating speed. For example, the operating speed of our space station is 7.68km/s, so it can circle the earth once every 90 minutes, and it is lower than the first cosmic speed of 7.9km/s.]

[Some people ask how can it be lower than the first cosmic velocity? Are you too unprofessional? Actually, it is possible. The reason will be explained later. First, let’s talk about the first cosmic velocity.]

[The first cosmic velocity actually has several names, namely the minimum launch velocity, the near-Earth satellite operating speed, and the maximum orbital speed. The reason why it is called the minimum launch velocity is that you can imagine throwing a stone from a mountain to a far distance. If the force is small, the stone will land close to the ground. The greater the force, the farther it will land.]

[That is, when your strength is strong enough to accelerate the stone to 7.9 km/s (F=ma), the stone will not fall down, but will move in a uniform circular motion around the earth]

[Why is it this value? Because the stone launched is similar to a near-Earth satellite, its orbital radius is close to the Earth radius R, and its centripetal force is provided by gravity. The formula is as follows: GMm/R= mv/R, which can be simplified to v = the square root of GM/R]

[Then it is a low-Earth satellite, and its gravitational force is almost equal to the gravity it receives, that is, replace the formula on the left, that is, mg = mv/R, and find the square root of v = gR. We know that g, G, and R are all constants, and their values ​​are respectively, so the minimum launch speed is 7.9km/s]

[As for why the space station does not fall when its speed is less than the first cosmic speed, it is very simple, because v = square root of GM/R. The smaller R is, the larger v is. When we calculate, we usually calculate the distance from the near-Earth satellite to the center of the Earth as the Earth's radius R. The speed v obtained in this way is the maximum orbital speed.]

[In actual situations, the orbital radius of a near-Earth satellite should be the radius of the Earth R + the distance from the satellite to the Earth's surface r, so its actual running speed must be lower than the first cosmic speed to be normal.]

[If there is a first cosmic velocity, there must be a second and third. The second cosmic velocity is also called the escape velocity, which refers to the minimum speed required to escape the earth's gravity. It is exactly twice the square root of the first cosmic velocity, which is 2km/s]

[After escaping from the earth, the satellite will be captured by the sun again, so the third cosmic speed is the minimum speed to escape from the sun, which is 16.7km/s]

In front of Fengtian Hall.

The crowd, who were originally watching the show, were caught off guard. Fortunately, they were well prepared and only needed to remember the second half, which was quite easy to remember. "This stone throwing animation is quite vivid. F=ma seems to be Newton's second law, right?"

Everyone recalled Newton's second law, and many people needed others' prompting before pretending to suddenly understand "Oh~"

Zhu Yuanzhang was so angry that he laughed. He certainly knew the character of his ministers. In fact, they might have just remembered it when Tianmu mentioned it half a year ago, and forgot it when they didn't need it later.

Fortunately, many people in the Science Department were dedicated and quickly pointed it out, and also mentioned the law of inertia.

Unfortunately, people don't know how the formula of universal gravitation was derived and can only memorize it by rote, just like Newton's three laws.

As the Science Department had guessed before, this universal gravitation is related to distance. As soon as we saw R, we knew that the guess was correct. Later generations generally used R and r to represent distance. It is also related to mass. M and m are both mass.

"It really has something to do with mass, two masses." Du Ping from the Science Department exclaimed. This is actually quite counterintuitive. For example, the mass of the moon must be much heavier than the apple on the tree, but the apple will fall down, but the moon will not.

So he just mentioned this speculation without any substantial evidence. Even he himself doubted it at the time, and it didn't cause much stir.

It is quite difficult to actually derive the formula of universal gravitation, and he still has no idea how to do it.

"What does centripetal force mean? Why are universal gravitation and gravity not equal?" Zhu Biao also noticed Tianmu's choice of words. Generally speaking, they were quite rigorous, so when they came across the word "almost equal", everyone was stunned.

"Also, when calculating the first cosmic velocity, they actually ignored the distance r between the satellite and the earth's surface. This is too inaccurate." A group of people complained at the same time.

"Could it be that the distance between the satellite and the earth's surface is too small? From the comments, I learned that it is 400km, while the radius of the earth is 6371km."

"That's not rigorous either."

The person who made the analysis stopped talking, but Zhu Yuanzhang still felt a little unbelievable and said, "With this theory, if there is a strong man, can we launch satellites now?"

"Your Majesty, it should be so."

"I never thought that we now even know the theories needed to launch satellites." Zhu Yuanzhang felt like he was in a dream.

"What do you think we should use our first satellite for?" Zhu Yuanzhang asked. He knew that satellites have many functions, such as weather forecasting, navigation, and agricultural monitoring.
Among them, navigation satellites are extremely important. They are said to be the eyes of various cars and ships, and are also essential facilities for missiles to hit whatever they are pointed at.

Missiles, satellites, and nuclear warheads, when combined together, they are formidable. If they act alone? They are worse than dogs.

Everyone was confused for a moment, but there were only two or three types of satellites that everyone was familiar with. After discussing for a while, if there was really no choice, "Navigation satellite?"

Zhu Yuanzhang laughed and said, "Great minds think alike. This navigation satellite is the most important weapon for our country. There are only four of them in later generations, and two of them are in semi-disabled state."

They also knew about GPS, Beidou, Galileo, and GLONASS from the video, but that video only gave a brief introduction to the names and their respective situations. Before that, no one had thought that satellites could be used to guide missiles to attack before the missiles turned.

Zhu Yuanzhang and his generals all thought that missiles were like artillery, and that once they were launched, they were done for. That was until they saw the video of a ballistic missile demonstrating its movement. It subverted everyone's worldview. It was as if the video was saying: My sword is 40 meters long, and you are allowed to run 39 meters first.

Of course, the real situation is the offensive and defensive battle between precision guidance and interception, which gave rise to such a magical scene.

But he also knew that this should be very difficult. He could clearly feel it, just like that mechanical fart kick and the robot, which was unpredictable and difficult.

Everyone started to giggle. What they were actually thinking was, don't be so obvious when you flatter someone. We are all educated people, so just be reserved.

"Isn't this a new Hollywood idea? I've even thought of titles for the film: Space Rescue, Gravity, and Critical XX Hours."

"Why is she so happy? This may not come back."

"It's better than being trapped on a spacecraft. In that situation, it wouldn't be too much to give the astronauts in the space station a few kowtows [cold sweat]"

"I watched the live broadcast last night. After the connection, no one in the control room cheered. I knew something was wrong, and it was a big problem [covering face]"

《Is it not open source? 》

Tang Dynasty, Chang'an City.

Li Shimin and others, who had just copied a few formulas, couldn't help but be choked. The corners of their mouths were inexplicably harder to suppress than AK.

Although they did not mean to gloat over other people's misfortune, they still saw from this accident the difficulty and rigor of launching a manned spacecraft. Any slight mistake could lead to a major accident.

If these two astronauts were trapped in space, unable to go up or down, who knows what unexpected things might happen. That is a place that even gods don't care about.

"Just thinking about it, the same seems to be true for a hot air balloon. If it suddenly loses control at the highest point and falls down."

".!"

Everyone was shocked and then broke out in cold sweats. They were completely blinded by their passion and believed in Tianmu's evil. How could they dare to get on a hot air balloon that had no protection and was only tied with a rope?

When the thing fell down, the rope was useless, and there was no straw or anything to pad the body with.

"This is pure murder for money!" All the generals could no longer hold back. Considering that the privacy in the palace might be violated, hot air balloons were not allowed to fly in the city.

Therefore, the hot air balloon business was set up in places far outside the city, and a group of generals often went there for excitement. Now thinking about it, I don’t know whether I should say that the quality of the hot air balloon is good, or be glad that I am lucky enough to have a tough life.

"Okay, stop talking nonsense. You are a fat man, Cheng Laohei. You won't die if you fall from such a high place!"

"What are you talking about!"

"Alright, alright, stop arguing and let's just forget about this." Li Shimin stopped them with a smile. They all knew that there was some truth in what he said. No one had ever thought about this issue before, and the hot air balloon just happened to have never had any accidents.

Although something bad was bound to happen sooner or later with that crude device, no one could come up with a better solution at the moment. The best solution was probably a flight ban, but that was unrealistic. After all, cutting off someone's financial resources was like killing their parents.

The next best option is to make a law to define the responsibilities and compensation standards of both parties, which is easy to do.
(End of this chapter)