初二物理课程总结（Physics course summary of junior middle school）.docVIP

初二物理课程总结（Physics course summary of junior middle school） Physics course summary for two days - Web search data Physics summary in junior middle school Chapter 1 preliminary knowledge of measurement I. measurement The process of measuring a physical quantity with an accepted standard quantity. Measurements should be made by measuring instruments, not by their own sensory organs. Two, length measurement International unit of length: M Conversion of units of length: 1 km = 1000 m = 103 M = 0.1 M = 1 DM 10 -1 meters 1 cm = 0.01 meters = 10-2 meters 1 millimeters = 0.001 meters = 10-3 meters =103 microns. The basic tool for length measurement: scale Three, error 1. the difference between the measured and the true is called error. 2., errors can be reduced by multiple measurements, averaging, but they can never be eliminated. 3. causes of errors: Measuring instruments are not absolutely accurate; The influence of temperature and humidity of the environment on measuring instruments; Measuring human visual differences. 4., the error is not wrong: error is inevitable, error can be eliminated. The second chapter, simple movement 1. mechanical movement What is mechanical motion? Movement is a polysemous word. The movement that we need to learn here is the object Position change. In order to define meaning, the change in the position of objects in physics is called mechanical motion. Relativity of motion and stillness To say whether an object is moving or stationary depends on which object is the other. The chosen object is called reference. Uniform rectilinear motion Constant speed or straight line motion is called uniform rectilinear motion. 2. speed and average speed Speed The rate of development and change of all things can be expressed by the word speed, such as the growth rate of plants, the rate of economic growth, etc.. In physics, velocity is used to indicate the speed at which an object moves. In uniform rectilinear motion, velocity is equal to the distance traveled b