The truth of Zhao Kuo's story What does Zhao Kuo's story tell us

Empty talk about theory cannot solve practical problems

On paper
What's the point of talking on paper?

On paper
It means that the theory of empty talk can not solve practical problems. It also means that empty talk can not become a reality
It is recorded in the biography of Lin Xiangru of Lianpo in historical records that Zhao Kuo, the son of Zhao she, a famous general of the state of Zhao in the Warring States period, learned the art of war when he was young, and his father couldn't beat him when he talked about military affairs. Later, he took the place of Lianpo and became general of Zhao in the battle of Changping
Its usage is formal; it is used as predicate, object and attribute; it has a derogatory meaning
People hate people who can only solve practical problems
The synonyms of "sit and talk", flashy, and satisfatory
The antonym is down to earth
Xiehouyu military thesis
Lantern riddle Sun Tzu; military book; military thesis; Zhao Kuo's war
An armchair strategy
allusion
During the Warring States period, Zhao Kuo, the son of Zhao she, a famous general of the Warring States period, was full of military knowledge. He was able to talk about how to use military. Even his father thought he was invincible. Zhao she thought he was a soldier on paper and didn't know how to change his mind. Later, Zhao she died and Zhao Kuo took the place of Lian Po. Lin Xiangru and others tried their best to fight against him. The king of Zhao insisted that Zhao Kuo lost 400000 soldiers in the battle of Changping
translation
During the Warring States period, Zhao she, a general of Zhao state, defeated the invading Qin army and was promoted to Shangqing by King Huiwen of Zhao state. He had a son named Zhao Kuo, who was familiar with military books since childhood and loved to talk about military affairs. Others often said that he could not do it. Therefore, he was proud to do it and thought that he was invincible. However, Zhao she was very worried about him and thought that he was just talking about military affairs on paper, And he said: "in the future, Zhao state will not use him as a general. If he is used as a general, he will surely make Zhao army suffer defeat." sure enough, in 259 BC, the Qin army invaded again, and Zhao army insisted on resisting the enemy in Changping (now near Gaoping County, Shanxi Province). At that time, Zhao she had died. Lianpo was in charge of the whole army. Although he was old, he still had a good way to fight, Knowing that it was not good for the Qin army to drag on, the state of Qin carried out an anti Japanese strategy and sent people to Zhao to spread the words that "the Qin army was most afraid of Zhao she's son, General Zhao Kuo". King Zhao was deceived and sent Zhao Kuo to replace Lianpo. Zhao Kuo thought he was very good at fighting, so he changed Lianpo's plan of war completely after Changping. As a result, more than 400000 Zhao troops were annihilated, He himself was shot dead by the Qin army

What's the reason for fighting on paper

This paper explains that war is discussed on paper. It means that empty talk can't solve practical problems. It also means that empty talk can't become reality. According to the biography of Lin Xiangru in historical records, Zhao Kuo, the son of Zhao she, a famous general in the Warring States period, learned the art of war when he was young

What's the way to decompose the force?

Orthogonal decomposition is to decompose a vector into two mutually perpendicular vectors. It is a method to decompose a force along mutually perpendicular directions (x-axis, Y-axis). From the point of view of the Vectoriality of force, it is the sub vector of force F. from the point of view of the calculation of force, the direction of force F can be expressed by sign, and the positive component indicates that the direction of sub vector follows

On the decomposition of forces
Sometimes it's horizontal and vertical, sometimes it's in the same direction as friction, if it's sliding down a slope

Let me teach you a trick: one is divided into two parts, and the two components should be vertical. Use sine and cosine to evaluate. If not, use orthogonal decomposition to draw a rectangular coordinate system, and use mapping to do it

Pull a wooden box with gravity g = 183n on the horizontal road surface with a rope. The angle between the rope and the horizontal road surface is 30 ° as shown in the figure. The dynamic friction coefficient between the wooden box and the road surface is μ = 0.10. In order to make the wooden box move in a straight line at a uniform speed on the horizontal road surface, what is the tension f on the rope?

The force analysis of the object is shown in the figure on the right, and the wooden box is acted by four forces. The pulling force F is divided into two components F1 and F2 according to the horizontal and vertical directions. From the balance of the two forces in the horizontal direction, we can get: F1 = FF = fcos & nbsp; θ & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; ① in the vertical direction: g = F2 + FN = FN + fsin θ & nbsp; & nbsp; and F2 = μ FN ③ A: the tension on the rope is 20n

As for the decomposition of force, the correct one in the following statement is ()
A. It is impossible for a force to be decomposed into two larger forces
B. It is impossible for a force to be decomposed into two equal forces
D. If the directions of two components, or the magnitude and direction of one of them, are known, then there is a unique solution to decompose the force

Correct answer D
When two forces are in opposite directions, fhe = F1-F2 can be F1 > fhe F2 > fhe. For example, the 2n force is decomposed into 5n7n with opposite directions, and both forces are larger than 2n
If two components are equal, the included angle is 120 ^ 0, and the resultant force is equal to one of the two components. If three components are equal, the resultant force is 0, B is wrong
If the directions of two components or the magnitude and direction of one of them are known, then the decomposition of the force must be unique (the component and resultant force form a closed vector triangle) d is correct

What is wrong with the following statement about the decomposition of forces
A an 8N force can be decomposed into two 8N forces
B an 8N force can be decomposed into two 4N forces
C a force of 8N can be decomposed into two forces of 13N and 6N
D a force of 8N can be decomposed into two forces of 16N and 7n

D wrong!
The resultant force of two forces must be greater than or equal to the difference between the two forces (when the two forces are in a straight line and in the opposite direction); less than or equal to the sum of the two forces (when the two forces are in a straight line and in the same direction)
The resultant force of 16 and 7 must be greater than or equal to 9, less than or equal to 23; it can't be 8

On the decomposition of force on inclined plane
Why does the gravity of an object placed on an inclined plane decompose into pressure on the inclined plane and a downward component? Is there any reason?

The gravity of an object placed on an inclined plane is decomposed into the pressure on the inclined plane and a downward component force, which is determined by the effect of the force. The gravity of an object causes the object to slide down the inclined plane and squeeze the inclined plane at the same time, so the gravity is decomposed along these two directions

Why can the gravity of an object resting on an inclined plane be decomposed into friction and elasticity?
Why should gravity, friction and elasticity be drawn in force analysis

Gravity can not be decomposed into elastic force and friction force. Gravity can be decomposed into two components, one along the slope and the other vertical slope. The nature of these two components is universal gravitation. We can use these two forces to replace gravity

The truth of Zhao Kuo's story What does Zhao Kuo's story tell us