Changxing Mingwang Rubber & Plastic Technologies Co.,Ltd. , https://www.cxmingwang.comJiangsu version compulsory one 1.3 "Acceleration" ppt 1) The vector physical quantity fully reflects the motion state of the object, which is convenient for theoretical derivation and general definition. At time t, the physical quantity describing the state of motion is 3) Generally, when solving a problem, it is necessary to select an appropriate orthogonal coordinate system according to the problem. Commonly used coordinate systems are: rectangular coordinate system, plane polar coordinate system spherical coordinate system, cylindrical coordinate system, etc.