(单词翻译:单击)
每日一题
Mathematics
](http://pic.kekenet.com/2018/0615/49431529028918.png "SAT官方每日一题附答案和解析[数学](2018年6月15日)")
Engineers at a theme park are recording the speed of a roller coaster as it travels over a particular hill. The graph shown above in the ds-plane represents the relationship between s, the speed of the roller coaster, in meters per second, and d, the distance along the track from the base of the hill, in meters. What is the best interpretation of the s-intercept marked on the graph?
A.The hill is 25 meters high.
B.The roller coaster has a speed of 25 meters per second at the base of the hill.
C.The roller coaster has a speed of 25 meters per second at the top of the hill.
D.When the roller coaster is 25 meters from the base of the hill, its speed reaches 0 meters per second and stops.
答案和解析
答案：B
解析：
Choice B is correct.
The s-intercept is the point (d,s)=(0,25). This means that the speed of the roller coaster is 25 meters per second 0 meters from the base of the hill.
The point 0 meters from the base of the hill is at the base of the hill. Therefore, the s-intercept means that the roller coaster has a speed of 25 meters per second at the base of the hill.
