论文部分内容阅读
一、单项选择题 1.分别在光滑和粗糙的水平面上推车,如果所用推力的大小、方向均相同,两车位移的大小、方向也相同,比较两种情况下推力所做的功,则:( ) A.在光滑的水平面上推力所做的功大. B.在粗糙的水平面上推力所做的功大. C.两种情况下推力做功相等. D.谁做的功大,取决于这一过程的时间. 2.汽车以恒定功率户由静止开始在平直公路上行驶,秒钟,速度达到v,产生位移为s,则在这段时间内,发动机所做的功是:( ) A.Pt/v. B.Ps/v. C.Ps. D.Pt.
First, single-choice questions 1. Cart on smooth and rough horizontal surfaces, if the thrust used is the same size, direction, the size and direction of the displacement of the two vehicles are the same, compare the thrust of the two cases of work done, then :( ) A. The thrust in the smooth horizontal surface does a lot of work. B. The thrust in the rough horizontal surface does a lot of work. C. The thrust is equal in both cases. D. Who does the merit, depends on At the time of this process. 2. The car starts at rest with a constant power on a straight highway. In seconds, the speed reaches v and the displacement is s. In this period of time, the work done by the engine is: () A.Pt/v. B.Ps/v. C.Ps. D.Pt.