论文部分内容阅读
全日制十年制学校高中课本《物理》上册第三章变速运动第二节练习一第(3)题的插图(如图1所示)是表示火车运动的位移—时间图象,题目要求根据图象回答一些问题,并画出火车的速度—时间图象。图2是按照图1位移—时间图象画出的速度—时间图象。如果追问:根据图1和图2所示的图象,试求出火车在1.5小时末与2小时末的即时速度各是多少? 一种答案是这两个时刻的即时速度分别为60千米/小时和50千米/小时,这可从OA段和BC段的斜率求得。另一种答案是这两个时刻的即时速度都为零,因为AB段的斜率等于零。
Full-time 10-year high school textbook “Physics” Volume I The third chapter of the variable speed movement Exercise II (Section 3) illustration (as shown in Figure 1) is to indicate the displacement - time image of the train movement. The image answers some questions and draws the speed-time image of the train. FIG. 2 is a velocity-time image drawn according to the displacement-time image of FIG. If you ask: Based on the images shown in Figures 1 and 2, what is the instantaneous speed of the train at the end of 1.5 hours and at the end of the 2 hours? One answer is that the instantaneous speed of the two moments is 60 kilometers respectively. /h and 50 km/h, which can be obtained from the slopes of the OA segment and the BC segment. Another answer is that the instantaneous speed at both moments is zero, because the slope of the AB segment is equal to zero.