Method | Application of methods in textbooks | Explain |
Wait effect law | (1) In the synthesis of forces, several components acting together can be equivalent to a combined force with the same effect; on the contrary, a force can also be decomposed into several components with the same effect. (2) In the circuit, several resistors can be equivalent to a suitable resistor. On the contrary, the total resistance of the series circuit and the total resistance of the parallel circuit all use the equivalent idea. (3) The equivalent of replacing elephants with stones in "The Elephant is Called by Cao Chong" has the same effect. (4) In the study of plane mirror imaging experiments, two identical candles are used, one of which is equivalent to the image of the other. | In physics, one or more physical quantities, a physical device, a physical state or process is replaced with another physical quantity, a physical device, a physical state or process, and the same conclusion is reached. Such a method is called Equivalent (replacement) method. The use of this method can make the problem to be studied simple and intuitive. |
Reason miss you mold type law | (1) Uniform linear motion is an ideal model. In real life, strictly uniform linear motion cannot be found, but there are many motion situations that are similar to uniform linear motion. Processing according to uniform linear motion greatly simplifies the difficulty, and the results obtained have extremely high accuracy. Consistent with the actual within the allowable error range. (2) Leverage is also an ideal model. In actual use, due to the effect of force, the lever will cause large or small deformations, which can be ignored. Therefore, we idealize the leverage and consider it to have no deformation. (3) During the flood season, the water in the river sometimes emerges from the ground outside the dam through the bottom layer of the dam, forming a "pipe surge". The physical model of the "pipe surge" is a connector. (4) Light and magnetic lines are hypothesized, but they express the physical situation and facts intuitively and vividly to solve the problem conveniently. The magnetic field is used to study the distribution of magnetic fields, and the path and direction of light propagation are studied through light. | It is an important physical idea to simplify complex problems, abandon minor conditions, grasp the main factors, idealize the actual problems, and construct idealized physical models. On the basis of establishing an idealized model, sometimes in order to more vividly describe the physical phenomena and physical problems to be studied, it is necessary to introduce some virtual content to express the physical situation visually and intuitively. |
control system change the amount law | (1) Study the relationship between sliding friction force and pressure and contact surface (2) Study the relationship between the effect of pressure (pressure) and pressure and area under pressure (3) Study the relationship between liquid pressure and liquid density and depth (4) Study the relationship between the kinetic energy of an object and its mass and speed (5) Study the relationship between the potential energy and the mass and height of the object (6) Study the relationship between the pitch of stringed instruments and the tightness, length, and thickness of strings (7) Study the relationship between current, resistance, and voltage, that is, Ohm's Law (8) Study the relationship between the resistance of the conductor and the material, length and cross-sectional area of the conductor (9) Study the relationship between the heat generated by the current and the current, resistance and energization time (10) Investigate the relationship between the magnetism of the electromagnet and the number of turns and current of the coil (11) Study the relationship between evaporation speed and liquid temperature, liquid surface area, and the speed of air flow above the liquid | When studying physical problems, a certain physical quantity is often affected by several different physical quantities. In order to determine the relationship between different physical quantities, it is necessary to control certain quantities to make them fixed and change a certain quantity. The relationship between a physical quantity and the physical quantity. [Note] This method is often used in many exploratory experiments. |
real Check Push Reason law | (1) Study Newton's first law (2) Study whether sound can be transmitted in a vacuum (3) The important conclusion that "there are only two kinds of charge in nature" is obtained through reasoning based on experiments. | The experimental reasoning method is based on a large number of reliable facts, based on real experiments, draws conclusions through reasonable reasoning, profoundly reveals the nature of physical laws, and is an important way of thinking in physics research. |
turn change law | (1) The current cannot be seen or touched. When judging whether there is current in the circuit, we can determine whether the light bulb in the circuit is illuminated. That is, based on the effect of the current (2) The molecular movement is invisible and inaccessible, which is difficult to study, but it can be understood by studying the phenomenon of diffusion (3) The magnetic field cannot be seen or felt. When judging whether the magnetic field exists, use a small magnetic needle to see if it is rotating to determine. (4) When judging the magnetic strength of the electromagnet, use the electromagnet to attract the pins to determine. | In physics learning, it is sometimes necessary to study invisible substances (such as current, molecules, forces, and magnetic fields). At this time, the research direction must be shifted to various visible effects and effects produced by the substance. Analyze and study the existence, size, etc. of this substance, this research method is called conversion method. Conversion as a way of thinking is often applied to analyze and solve problems. |
class ratio law | (1) Water current is compared to current when studying current (2) Analogy of "voltage" with "water pressure" (3) Analog power supply with water pump (4) Studying the speed of doing work and the speed of exercise (5) Analogy of electric potential energy and gravitational potential energy in electric field, etc. | In order to make the physical problem to be expressed clear, concrete, tangible, and well-known things are often used to analogize those abstract, intangible, and strange things to be explained. Through analogy, people can have a direct, concrete, and visual understanding of the things to be revealed, and find similar laws. [Note] An analogous two or two types of objects must have the same or similar things in common. |