外力对物体所做的总功等于物体动能的变化时,可应用动能定理,应用动能定理必须明确下述两点。 一、定理仅适用于质点 通常认为动能定理仅适用于单个物体。从课本中对动能定理的推证过程看,定理中所说的“物体”系指质点而言,不能视为质点的物体,不能应用动能定理。 When the total work done by an external force on an object is equal to the change in the kinetic energy of the object, the kinetic energy theorem can be applied. The following two points must be made clear when applying the kinetic energy theorem. 1. The Theorem Only Applies to Particles It is generally accepted that the kinetic energy theorem applies only to a single object. From the textbook’s process of certifying the kinetic energy theorem, the “object” in the theorem refers to an object that cannot be regarded as a particle in terms of a mass point, and cannot use the kinetic energy theorem.