物理量根据其有无方向性可以分成矢量和标量.某一物理量如果既有量的大小又有方向性,则为矢量;如果只有量的大小没有方向性,则为标量.例如位移、速度、电场强度、磁感应强度等为矢量,时间、质量、功、能等为标量.学生在初中虽然对速度、力等量也有方向性的认识,但没有建立矢量概念.而且由于初中一般只研究一维运动,不强调位移和路程的差别,所以学生对矢量只获得要么加要么减的认识,对“匀速”的认识是速度大小均匀不变,认为绕操场均匀地跑一圈是匀速运动, Physical quantities can be divided into vectors and scalars according to their directionality. A certain physical quantity is a vector if it has both magnitude and directionality. If only the magnitude of the quantity has no directionality, it is a scalar. For example, displacement, velocity, and electric field. Intensity, magnetic induction, etc. are vectors, and time, quality, work, energy, etc. are scalars. Although students have directional knowledge of speed and force in junior high school, they do not establish vector concepts. Since junior high schools generally only study one-dimensional movements. Does not emphasize the difference between displacement and distance, so students only get the knowledge that the vector is plus or minus, and the understanding of “uniform speed” is that the speed is uniform and uniform. It is considered that the uniform running around the playground is a uniform movement.