Achievements of physics in ancient China Don't need too complex, brief introduction, can introduce people and things clearly

Achievements of physics in ancient China Don't need too complex, brief introduction, can introduce people and things clearly

The achievements of physics in ancient China -- the book of changes
Living things are special objects which are totally different from non living things. Non living things form natural phenomena, while living things are the main body of life phenomena (such as society, consciousness, thought, special function, telepathy, intelligence, vitality, soul, bioenergy, etc.). They have totally different properties and phenomena, so they must have different compositions and structures, Molecules constitute cells, and cells constitute organisms. Between molecules and cells, there are also Qi substances, that is, Qi body, which are meridian and acupoint substances, Biology is a unified organic whole composed of four systems: solid bone and flesh hair nail, liquid body fluid (body fluid and blood), gas state respiratory and digestive tract, and energy state meridians and acupoints. Solid liquid gas three states constitute the body system of biology, and energy state meridians constitute the consciousness system of Biology, Moreover, the energy state is the key system to determine life activities, without the energy state system
The advanced nature of space and time in Europe, people's understanding of time and space was fragmented and isolated. Until the early twentieth Century, relativity had unified the space and time scientifically. But in ancient China, many philosophers had taken time and space to connect them in the pre Qin period. It is said that "heaven and earth, the unity of all things, the unity of universe and heaven and earth", which means that all things are contained in heaven and earth, and heaven and earth are contained in the "unity of universe" of time and space. Mohist's understanding of time and space has a new development. They call space "universe", including various places and directions in southeast, northwest, and all directions, and call time "long." Yujiu "is the modern universe
Huishi of the Warring States period, the most famous proponent of the theory of infinite separability of matter, has realized that "the smallest is no interior, which means that the constituent unit of matter has no interior limit and is infinitesimal. His contemporaries also use specific metaphors to explain the infinite separability of matter, that is," the beating of a day, half of the day, and the world is endless. ", It reflects the dialectical nature of nature more deeply than the atomism of ancient Greece
The understanding of snowflake crystals in ancient Europe began in the 13th century. Albert said in 1260 that "snowflakes are star shaped." however, the understanding of the hexagonal symmetry of snowflake crystals was not realized in the West until Kepler. In 1611, the understanding of the hexagonal symmetry of snowflake crystals was not realized, Kepler affirmed the hexagonal crystal structure of snowflakes in his paper "taking hexagonal snowflakes as a new year's gift". The understanding of the hexagonal symmetry of snowflakes in ancient China began with Han Ying in the Western Han Dynasty. In 135 BC, he said in the biography of Han Poetry: "five more plants and flowers, six more snowflakes." this is more than ten centuries earlier than Europe
A water jet fish wash is made by using the vibration principle. It is similar to a copper plate, and its outer edge has a pair of symmetrical ears. When the basin is filled with water, such as the back and forth rubbing the ears of the copper basin, it will produce a buzzing sound. At the same time, a water column rises from the water surface. As early as in the Five Dynasties of China, Jin was defeated by Liao, When the Jin emperor surrendered (946), he contributed a Pisces porcelain basin which can spray water to Emperor Taizong of Liao Dynasty. This is the earliest water fish wash recorded in Chinese ancient books. The bronze water fish wash appeared in the late Northern Song Dynasty, and the agate water fish wash appeared in the Xuanhe period (1119-1125)
The principle of fish washing water spray is vibration, a regular plate vibration similar to a cylindrical plate. The vibration is transmitted from the ears to the side wall, resulting in a transverse vibration perpendicular to the water surface, making the water surface splash
The study of plate vibration in the West began in the second half of the 18th century in Germany. In order to make the plate vibration visible, he sprinkled a thin layer of sand on the metal plate, then knocked the metal plate to make it vibrate, and the fine sand on the plate moved to those non vibrating nodal lines. The various vibration patterns he drew from this are the pictures of the krasney sand. The water spray fish washing in China was seven centuries earlier than the krasney vibration plate
The understanding and experiment of resonance phenomenon in ancient China has been recorded for a long time. The book Zhuangzi from the 3rd century to the 4th century B.C. recorded the resonance phenomenon in tuning the harp. The discovery of this kind of fundamental and overtone resonance phenomenon is much earlier than that in the West, In Europe, it was not until the 15th century that Leonardo da Vinci carried out the first resonance experiment. Mozi's chapter on cave preparation also describes the specific application of resonance phenomenon: dig a pit every few meters under the root of the city wall, and bury a 70-80 liter earthenware urn in the pit. The mouth of the urn is covered with leather. If an enemy attacks a city by digging a tunnel, the position and direction of the enemy's excavation can be determined according to the sound of each earthenware urn
Ancient China not only understood the phenomenon of resonance very early, but also mastered the method of eliminating resonance. The Tang Dynasty's book "the record of the guests of Liu Jiahua" recorded a story in this respect: there was a chime hanging in a monk's room in Luoyang, which often sounded itself. The monk was so worried that he became ill. One day, his friend Cao shaokui came to visit and found that the chime was caused by the bell of the temple, He filed the chime a few times. Sure enough, the chime stopped ringing when the clock rang again
In the early years of A.D., Wang Mang reformed the world's earliest vernier caliper and made a kind of copper caliper. It is 14.22cm long and divided into two parts: fixed ruler and movable ruler. The front of the ruler is engraved with the scale of inch and grade. From the principle, performance and use, this vernier caliper is very similar to the modern vernier caliper, but it is more than 1700 years earlier than the vernier caliper made by Western scientists
The Changan incense burner was invented by Ding Huan, a craftsman of Chang'an. When the sandalwood blocks in the incense burner are ignited, the incense burner can be put into the quilt. Not only the quilt will not be burned, but also the incense burner ash will not come out. The secret is that there is a device called "Changan incense burner", which is composed of two metal rings inside and outside, The two rings are connected by a rotating shaft, and the outer ring is connected with the outer frame by another rotating shaft. This kind of gimbal device is widely used in modern navigation magnetic compass and electric compass. The gimbal device did not appear in Europe until the 16th century, more than 1600 years later than China
There are still many physics related inventions and discoveries in China, such as the discovery of magnetic declination and inclination, the use of solar energy, periscope, transparent copper mirror, linear propagation of light, pinhole imaging, twelve average law, etc

It's a traditional physics problem
A block of mass m is placed on the slope of a triangle of mass m (right triangle, m on the slope)
The angle between the bevel and the horizontal plane is a. the bevel is placed on a smooth horizontal plane
All contact surfaces are smooth
Now release m from the top of M. find the acceleration and direction of M

I think I did this many years ago
It's not that simple
Definitely not gsina down the slope
Since m tends to move to the left, m tends to move in the inclined plane
That is to say, the angle between the acceleration of M and the horizontal direction is θ, and θ is greater than the inclined plane angle α
solution
Let the supporting force of the ground to m be n, and the supporting force of the inclined plane m to m be N1 perpendicular to m upward
The acceleration of M is A1 to the left
The acceleration of M is A2, which is in the direction of θ and lower right
Newton's law is used to analyze the whole force in the vertical direction
Mg+mg-N=m a2 sinθ (1)
Newton's law is used to analyze the overall force in horizontal direction
M a1=m a2 cosθ (2)
Analysis m in horizontal direction
N1sinα=Ma1 (3)
Horizontal analysis m
N1sinα=m a2 cosθ (4)
Analysis m in vertical direction
N1cosα+Mg=N (5)
Vertical analysis m
mg-N1cosα=ma2sinθ (6)
Remove A2 and θ
It's hard to understand. The ink is dead
Take it off later
(1)^2+(2)^2=1
(Mg + mg-N) ^ 2 + (MA1) ^ 2 = (ma2) ^ 2 (7) (unknown n A1 A2)
(3) (5) Tana = MA1 / (n-mg) (8) n A1
(4) ^ 2 + (6) ^ 2 + (5) * 2mg
N1 ^ 2 + m ^ 2G ^ 2-2mg (mg-N) = m ^ 2A2 ^ 2 (9) unknowns n A2 N1 {replace (4) with N1}
Sorting 8 and 9 substituting A1 =? A2 =? (containing n) into (7)
Get n
Then we get A1, A2, and substitute (2) to get θ
I'm too lazy to take the next few steps