Before Wang Xiang finished speaking, he had already rushed out. With the initial velocity of v=5m/s to do a uniform acceleration linear motion of a=2m/s2, it didn't take long for Wang Xiang to reach the vicinity of the toilet of the No. 2 Middle School, and he was about to leave the school gate after turning a corner.

To chase or not to chase, Niu Zihao was unusually entangled. Chase it, what if I can't catch up, won't it make me run in vain. If you don't chase it, won't the five-yuan beef noodles and the three-dollar eggs be in the soup? Oh, they were originally soaked in the soup, Niu Zihao suddenly realized.

Knowing that Wang Xiang's initial velocity v = 5 m/s and acceleration a = 2 m/s2, Niu Zihao visually measured the change in the distance of Wang Xiang's movement △ x = 300m. According to the acceleration formula △x=at2, t=±√△x/a, excluding a negative answer. Then the time t=√300m/2m/s2=√150s, Niu Zihao has made a simplified processing here, and the √150s is directly equal to √160s=4√10s. Obviously, 4√10 should be less than 5s, and if Niu Zihao wants to catch up with Wang Xiang, he must walk a distance of 300m in 4s.

According to v=s/t=300m/4s=75m/s, Niu Zihao must travel 75 meters per second, and after 4 seconds, it is possible to catch up with Wang Xiang.

At 75 meters per second, this is not a speed that a person can reach. So Niu Zihao had a whim, and used the Xueba god-level system to set the time to be 4 seconds and the speed to be 75m/s. A gust of wind that could only hear "whoosh" flashed in Niu Zihao's ears, and Niu Zihao began his 4-second campus journey.

"Did you just see something flying by?" A female teacher who teaches physics asked.

The teacher next to him just lowered his head and played Kuaishou, and didn't see anything.

As soon as Wang Xiang stepped out of Anqin County No. 2 Middle School, Niu Zihao chased after him from behind, and Wang Xiang's face was pale with fright. One didn't stand still and almost fell to the ground.

"Niu Zihao, are you so aggressive about a bowl of beef noodles, you can run faster than Liu Xiang." Wang Xiang was already out of breath, panting heavily.

Niu Zihao smiled helplessly, and said: "Wang Xiang, in fact, this is not a question of a bowl of rice, but a question of a person's character and morality. I don't know if your three views are correct, your outlook on life, values, and society. But I can tell you very clearly that your thinking and morality have been distorted. ”

said a lot, Wang Xiang listened to the clouds.

In fact, it was Niu Zihao who misunderstood Wang Xiang, and he was originally out of kindness and wanted to leave the campus as soon as possible. This will not only occupy a good seat, but also eat deliciously. If you delay for a few more minutes, you will probably have to wait in a long line to buy tickets.

Under Wang Xiang's repeated explanations to Niu Zihao, the two of them released their suspicions, and this page was turned over.

When I came to the Tip of the Tongue Beef Noodle Restaurant near No. 2 Middle School, the owner of the restaurant greeted every customer warmly.

"Two bowls of beef noodles, four eggs, two plates of side dishes, give you 20 yuan, don't look for it." Wang Xiang said very calmly and calmly, and it could be seen that he was a frequent visitor here.

After the cashier's lady typed the ticket, she thought about it carefully, what does it mean that you don't need to look for it, you don't look for it at all. I thought he was making a generous shot, but I didn't expect him to make up an integer, so he was really speechless.

At the moment when Wang Xiang received the money from the young lady, Niu Zihao used the Xueba god-level system to make a rough calculation. Two bowls of beef noodles 2×5 + four eggs 4×1 + two plates of side dishes 2×3=10+4+6=20 (yuan), just 20 yuan, of course, don't look for it.

After inquiring about Niu Zihao's noodle eating, Wang Xiang said to the ramen chef: "Two bowls and two fine, put a little more chopped green onions." ”

"Okay." The ramen chef also replied enthusiastically.

In the corner of the wall, Niu Zihao had already sat down. The side dishes were ready, and the red date tea was also served into the cup by Wang Xiang. Everything is ready, only two details are owed.

……

The beef noodles just out of the pot are a little hot, like a burning fire, and just like the scorching heat and drought resistance. The disposable chopsticks were disassembled, and the eggs that had already been peeled were submerged into the soup by Niu Zihao with chopsticks.

Pour some vinegar, Niu Zihao picked up a pinch of noodles and began to taste carefully. Eating and eating, Niu Zihao ate a taste of hometown, strong and innocent.

Watching Niu Zihao eat with relish, it was difficult to swallow when he came to Wang Xiang's side. How Niu Zihao eats beef noodles, giving people the feeling of enjoying a sumptuous dinner. In short, Niu Zihao's impression of Wang Xiang was very peculiar, and he felt that this person was a little confused.

How can you just eat beef noodles, how boring! couldn't bear the loneliness, so Wang Xiang went to the bar and ordered a glass of cold Coke. I heard that on a rainy day, cola and beef noodles go well together!

Unexpectedly, when Wang Xiang returned to his seat again. He found a person, a girl, who was sitting behind Niu Zihao at this time.

It turned out that I met a senior sister who played table tennis in physical education class, and it was really fateful. Wang Xiang was pondering, but fortunately, between my senior sister and me, there was also a Niu Zihao eating noodles. If I really want to be with my senior sister, I guess I will have to sweat my nervous palms.

Wang Xiang is about to eat most of the bowl of noodles, in order to strive for a longer time with his senior sister. Wang Xiang changed his strategy and chewed slowly one by one.

Niu Zihao was eating, and suddenly a small story flashed in his mind, which was a legend of Archimedes.

Legend has it that in 245 BC, King Henon ordered Archimedes to authenticate a crown. King Henon gave the goldsmith a piece of gold and asked him to make a crown of pure gold. Although the crowns were as heavy as the previous gold, the king suspected the goldsmith of adulteration.

He ordered Archimedes to determine whether the crown was pure gold, but not to destroy it. It seems impossible. Inside the public bathhouse, Archimedes noticed that his arm was floating to the surface. A vague thought flashed through his mind. He lowered his arm completely into the water and relaxed, at which point his arm floated to the surface again.

He stood up, and the water level around the tub dropped; When I sat down again, the water level in the tub rose again.

He lay in the tub, the water level became higher, and he felt himself lighter. When he stood up, the water level dropped and he felt heavy. It must have been the upward buoyancy of the water on his body that made him feel lighter.

He put a stone and a block of wood about the same size into the tub at the same time and immersed it in the water. The stone sank into the water, but he could feel it lighter. Moreover, he had to press down on the block to completely submerge it in water. This suggests that in the case of sinking, buoyancy is related to the displacement of the object (object volume) and not to the weight of the object. The perceived weight of an object in water must be related to its density (the mass of the object per unit volume) at the same mass.

Most importantly, Archimedes discovered the principle of buoyancy, which states that the buoyant force of water on an object is equal to the weight of the water discharged by the object.

From this, the formula of Archimedes' principle can be obtained: F float = p liquid gV row.

According to the formula, Niu Zihao made many complex assumptions in his mind before finally calculating the buoyancy of the beef noodles.