关于“动能”概念，统编物理教材是这样引入的：设质量为m的物体原来静止，在恒力F的作用下发生一段位移S，得到一个速度v（图一）。力F对物体所做的功W=FS。根据牛顿第二定律，F=ma，另外，从运动学的公式v~2=2aS， With regard to the concept of “kinetic energy,” the textbook for physics was introduced in this way: Let an object whose mass is m be stationary, and a displacement S occurs under the influence of constant force F to obtain a velocity v (Figure 1). The work done by the force F on the object W = FS. According to Newton’s second law, F=ma, in addition, from kinematics formula v~2=2aS,