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What is the reason why China's legitimate seat in the United Nations has been restored and China US relations have begun to normalize? A successful development of atomic bomb B improvement of China's comprehensive national strength
The continuous improvement of China's international status and the changes in the international situation
There are three basic forms of describing physical laws,
Any physical law can be expressed in words, mathematical formulas and images. Therefore, when learning physical laws, we should understand, remember and apply them in an all-round way from these three aspects
Three methods of physically controlling noise
1: Attenuation at sound source
2: Weaken in the process of transmission
3: It weakens in the human ear
This is what I learned in physics class today! The answer given by the teacher
Questions about three states (elementary physics) Let's talk about the following main examples of physical changes vaporization liquefaction freezing melt sublimation Ninghua
Vaporization is liquid to gas, and water evaporates
Liquefaction refers to the process from gaseous state to liquid state, and the water vapor with higher temperature to the place with lower temperature. The outer layer of cold water drunk in summer is formed by liquefaction
Solidification, liquid to solid, freezing
Melting, solid to liquid, solid to liquid at high temperature, steelmaking and ironmaking
Sublimation, solid to gaseous, a few substances directly to gaseous without liquid, iodine sublimation
Condensation, gaseous to solid, the above physical state in turn, iodine condensation
See
What are the three basic forms of describing physical laws?
Any physical law can be expressed in words, mathematical formulas and images. Therefore, when learning physical laws, we should understand, remember and apply them in an all-round way from these three aspects
Emotional atmosphere method
Emotion is people's positive or negative psychological response to external stimuli. People's thinking activity is closely related to the state of emotion
The so-called emotional atmosphere method refers to a method that teaches people to use certain emotional factors to deliberately create a certain emotional atmosphere, so as to enhance people's ability to actively explore and learn things, so as to activate people to treat things positively
RELATED INFORMATIONS
- 1. What is the noun interpretation of law?
- 2. How to understand the true meaning and revolutionary nature of Hegel's philosophy and the internal contradiction of Hegel's philosophy?
- 3. Formula for calculating magnetic field strength Calculate the strength of the magnetic field at that distance angle
- 4. Energy variation in mechanical waves Where does the mechanical wave have the greatest kinetic energy? Where is the greatest potential energy? How does the energy change as the wave propagates?
- 5. What is the formula of free fall What does s in the formula mean
- 6. A sound source vibrates 720 times in 2 minutes. What is the frequency
- 7. What is the sound source when beating the drum
- 8. Sound travels in the form of waves, which we call ()
- 9. How does the sound from the vibration of the sound source reach our ears
- 10. Chapter II section I generation and transmission of sound 1. Look at the four pictures in figure 2.1-1. Answer: the beautiful sound in the first picture is the string_________ Issued; A moving song is a vocal cord_________ Issued; The deafening waterfall sound in the second picture is the sound of water_________ Issued; In the third picture, the noise of electric grinding wheel is grinding wheel noise_________ Issued; In the fourth picture, the chirping of a toad is a chirping sac_________ Issued; In Figure 1-2, the male cicada chirps by means of the ventral articulator________ And the mosquito's "bark" depends on_________ Yes_________ It can be seen that the common feature of objects when they sound is that they are _____, Sound is made by objects________ The object that is vibrating and making sound is called ____ 2. Strike the gong and bell. The gong and bell sound endlessly because they are still ____ Cover the surface of the Gong quickly with your hand, and the sound of the Gong disappears quickly, indicating_________ Stop making sound stop
- 11. Hawking introduction
- 12. On December 26, 2004, a century tsunami occurred, but animals did not die on a large scale. From a physical point of view: () A some animals can hear ultrasonic waves B some animals can hear infrasound waves
- 13. The artificial satellite makes a uniform circular motion around the earth, its orbit radius is r, its linear velocity is V, and its period is t. if you want to change the period to 2T, what methods can be adopted: A. R remains unchanged, so that the linear velocity becomes 1 / 2V, B.V remains unchanged, and the orbit radius becomes 2R C. yes, the orbit radius becomes (3 times better, 4 times lower) d. increase the height of the satellite by R
- 14. The object changes speed under the action of external force When an object changes speed under the action of external force, the kinetic energy must change The kinetic energy of an object remains unchanged, and the combined external force must be zero Why are these two sentences wrong?
- 15. A physics problem about uniform variable speed linear motion in high school (about the proportional relationship in special laws) A train starts to move at a constant speed in a straight line from a standstill. One person stands in front of the first carriage to observe. The time for the first carriage to pass through him is 4 seconds, and the time for all trains to pass through him is 12 seconds. The distance between carriages is not recorded, and the length of each carriage is equal. It is required to (1) how many carriages in total; (2) How many cars passed this person in the last 4 seconds; How many seconds did the last three sections pass through this person? I hope it's best to use the proportional relationship in the special law, and attach the description and analysis, not just the formula and answer If the three questions are difficult to answer, you can answer the first one first
- 16. A car traveling along a straight highway with uniform acceleration, passing two electric poles 50m apart by the roadside, shares 5S. When it passes the second electric pole, its speed is 15m / s, and when it passes the first electric pole, its speed is () A. 2m/s B. 10m/s C. 2.5m/s D. 5m/s
- 17. Particle is an idealized model. In the following examples, what can treat the research object as a particle is () A. Study the motion law of the earth around the sun B. Study the law of the alternation of day and night on the earth C. Study the time required for the train to run from Fuzhou to Shanghai D. Study the time required for a train to pass the Nanjing Yangtze River Bridge
- 18. The time taken for an object to fall freely after the last 200 meters is 4 seconds, then what is the falling time and total height of the object
- 19. How to use the formula of uniform variable speed linear motion in senior high school physics compulsory 1 Is under what circumstances this formula is used
- 20. The derivation of the relationship between velocity and displacement in free fall motion