Question

汽车 $M$ 以恒定速度行驶了一段给定时间，如虚线所示。汽车 $N$ 以两倍速度行驶相同距离。如果用实线表示汽车 $N$ 的速度和时间，哪张图表示这种情况？

Car $M$ traveled at a constant speed for a given time. This is shown by the dashed line. Car $N$ traveled at twice the speed for the same distance. If Car $N$ 's speed and time are shown as a solid line, which graph illustrates this?

答案：D

知识点：路程、速度与时间数据与图表解读

难度评级：1430

解答：

汽车 $N$ 的速度是汽车 $M$ 的两倍，所以它在速度轴上的高度应是汽车 $M$ 的两倍。

因为汽车 $N$ 以更快速度行驶与汽车 $M$ 相同的距离，所以它用一半时间完成行程。

因此表示汽车 $N$ 速度的线段长度是表示汽车 $M$ 速度的线段长度的一半。

两条线都水平，因为速度恒定。查看给出的图，唯一满足条件的是图 D。

所以正确答案是 D。

Car $N$ travels at twice the speed of car $M,$ so it is represented by a point that is twice as high on the speed axis as car $M.$

Since car $N$ travels at the same distance as car $M$ but at a faster speed, it takes half the time to complete the trip.

Therefore, the line representing car $N$ 's speed is half the length of the line representing car $M$ 's speed.

Both lines are horizontal because the speeds are constant. Examining the given graphs, the only one that meets these conditions is graph D .

Thus, D is the correct answer.

2001 AMC 8 第 19 题

答案：D

难度评级：1430

解答：

其他年份的第 19 题