幂函数方面的问题Thestoppingdistanceofanautomobileisdirectlyproportionaltothesquareofitsspeed.Acarrequired65feettostopwhenitsspeedwas40milesperhour.Findamathematicalmodelthatgivesthestoppingdistanceinterm

Question

幂函数方面的问题
The stopping distance of an automobile is directly proportional to the square of its speed .A car required 65 feet to stop when its speed was 40 miles per hour.Find a mathematical model that gives the stopping distance in terms of its speed .
Your answer is d=
停车需要的距离d和它的速度v的平方成正比,车速为40公里每小时的车,停车需要65米.求d的方程式

Answer 1

【参考答案】
根据题意,设d=kv²,
把（40,65）带入上式得
65=40²k
k=65/1600=13/320
∴ d=13v²/320