Question

火车从甲站到乙站正常行驶速度是60 km/h,有一次火车从甲站开出,由于迟开了5分钟,司机把速度提高到72 km/h,才刚好正点到达乙站。求:

(1)甲、乙两站间的距离;

(2)火车从甲站到乙站正常行驶的时间。

Answer 1

【解析】设正常行驶时所用时间为t,甲、乙两站间的距离为s,正常行驶速度v₁=60 km/h=m/s,提高后的速度v₂=72 km/h=20 m/s,则:

v₁t=s                                                                           ①(3分)

v₂(t-60×5)=s　                                                             ②(3分)

将已知数据代入①②式解得:

t=1 800 s=0.5 h　                                                               (3分)

s=30 km　                                                                       (3分)

答案:(1)30 km　(2)0.5 h