From the idiom story of "a blessing in disguise", we can understand the meaning of Laozi's "misfortune is the source of happiness; happiness is the source of misfortune", and give another example to illustrate it in real life From the idiom story of "a blessing in disguise", can you understand the meaning of Lao Tzu's sentence "misfortune is the source of happiness; happiness is the source of misfortune"

It shows that good and bad things in the world are not absolute. Under certain conditions, bad things can lead to good results, and good things can also lead to bad results. [source] words see (the seventh biography of Feng Yi, Volume 17 of the later Han Dynasty, written by Fan Ye of the Southern Song Dynasty): "Xi Shu Lao Yi said:" red eyebrows break flat, officials work hard. Although they first hang their wings back to the stream, they can finally stride in the pool. It can be said that "the East is lost.", The reward of the merit is in return for the great merit. "
[use case] (cold eye view Chapter 20 by Wang Junqing of Qing Dynasty): "who knows that old lady Qi, still a thief, wants to" lose the East and get the mulberry elm ". He dares to go to a big shop in Xiaogan county and still do it. This time, he is full of evil and reveals himself."
[commentary] after Liu Xiu became Emperor Guangwu of the Eastern Han Dynasty, he sent General Feng Yi to lead his troops to the west to fight against Chimei. Chimei feigned defeat and defeated Feng's troops in Huixi, But in the end, he can win in Mianchi. It can be said that there are some losses here, and then there are gains there
(2) Sangyu: the place where the sun sets, that is, the night, that is, the end
It means to lose something in one place and gain something in the other. It means to fail on one side and achieve something on the other

In life, it's like a blessing in disguise```
Give an example of the mutual transformation of opposites like misfortune and happiness in real life```

In fact, a lot of them, but we didn't pay attention to them
For example, the Opium War did cause great trauma to China at that time, but it also opened the awakening of the Chinese people and laid the foundation for China's independence today
In life:
Muddleheaded child, his finger was hurt by broken glass for the first time, but because of this understanding, he won't be hurt by glass next time

Give examples to illustrate the role of laws and regulations in public life

For example, the road traffic safety law, we abide by in order to maintain good traffic order

Determination of acetylsalicylic acid in aspirin

Acetylsalicylic acid, commonly known as aspirin, is an important medicine. It has antipyretic, analgesic and anti rheumatic effects. 2. Basic principle: acetylsalicylic acid is prepared by dehydration of salicylic acid (o-hydroxybenzoic acid) and acetyl anhydride catalyzed by a small amount of concentrated sulfuric acid (or dry hydrogen chloride, strong organic acid, etc.)

Why use neutral ethanol instead of water in titration analysis of aspirin

First, because aspirin is easily soluble in ethanol and slightly soluble in water, using ethanol can reduce the error
Secondly, the acetyl group will hydrolyze, so neutral ethanol is used to prevent hydrolysis

On a long enough inclined plane with an inclination of 37 degrees, an object with a mass of 2kg is released from rest. The air resistance is proportional to its velocity (F = kV), and the final sliding velocity of the object is 2m / s. The dynamic friction coefficient between the object and the inclined plane is known to be μ = 0.3, and G is taken as 10m / S2

According to Newton's second law, mgsin37 ° - f-fn = ma (1) and f n = μ n = μ mgcos370 (2) and F = kV (2), the solutions of the above equations are obtained

A train is 100 meters long and runs at a normal speed of 20 meters per second. When passing a 1000 meter long bridge, the train must run at a speed of 10 meters per second, and the acceleration is 0.5 meters per square second?

The time of variable speed movement is t1:1
The deceleration and acceleration time is t = (20-10) / 0.5 = 20s
Driving distance during deceleration: L1 = v1t-1 / 2at ^ 2 = 20 * 20-0.5 * 20 ^ 2 * 1 / 2 = 300m
Driving distance during acceleration: L2 = v2t + 1 / 2at ^ 1 = 10 * 20 + 0.5 * 20 ^ 2 * 1 / 2 = 300m
Bridge crossing time t0 = (1000 + 100) / V2 = 110s
So the total time is T1 = t0 + 2T = 150s
T2 = (300 + 100 + 1000 + 300) / V1 = 85s in uniform motion
So the delay time T1-T2 = 65s
The data is for reference only

A and B are two objects moving along the prescribed positive direction on the same straight line, a a = 4m / S2, a B = - 4m / S2
A. The acceleration of a is greater than that of B. the direction of acceleration of a and B must be opposite. C. the direction of acceleration and velocity of a is the same, and the direction of acceleration and velocity of B is the same. D. the magnitude of velocity of a and B is increasing

A. The acceleration is a vector, and the negative sign indicates the direction, so the acceleration direction of a and B objects is opposite, and the size is equal, so a is wrong; B, C, from the meaning of the title, we can see that the motion direction of a and B objects is the same, and they are both positive; the negative sign of the vector indicates the direction, but it does not indicate the size, so the acceleration and velocity direction of a are the same

Parachutists perform low altitude parachute jumping. When the plane is 224 meters above the ground, the athletes leave the plane to do free fall movement in the vertical direction. After a period of movement, they immediately open the parachute. After the parachute exhibition, the athletes decelerate and descend with the acceleration of 12.5 meters per second. For the safety of the athletes, the maximum landing speed is required to be no more than 5 meters per second, g = 10 meters per second
1. How much is the distance from the ground when the athlete unfolds the parachute? How high is the free fall when he lands on the ground
2. What is the shortest time for an athlete in the air

Let the parachute open after T seconds of free fall, the velocity is GT, the height of free fall is h = 1 / 2 * GT ^ 2, the initial velocity of uniform deceleration is GT, the final velocity is v = 5, the acceleration is - 12.5, and the displacement is 224-h. from the velocity displacement formula of 5 ^ 2 - (GT) ^ 2 = 2 * (- 12.5) * (224-1 / 2 * GT ^ 2), t = 5s1, and the ground clearance is 224-1 / 2 *

When an object rushes onto a smooth slope at a certain initial velocity, the displacement in the first four seconds is 1.6 m, and then the displacement in the next four seconds is zero, how much is the acceleration of the object? (let the object move at a constant speed)

We use the inverse process to solve this problem, which is equivalent to the object from the highest point a to do the uniform acceleration linear motion with zero initial velocity, the BC interval is 1.6m, the time T2 = 4S, the time interval between AB is T1 = 2S, according to the displacement time relation: XAB = 12at12 ①xAC=12a（t1+t2）2… ② Because XAC XAB = 1.6m ③ A: the acceleration of the object is 0.1m/s2

In life, it's like a blessing in disguise``` Give an example of the mutual transformation of opposites like misfortune and happiness in real life```