Explain it clearly.
1. A girl walks on a straight road from A to B with constant speed of 2m/s. Then she walks from B back to A with constant speed of 3m/s. If A and B are 10m apart, what is her average speed for the whole trip?
A question
2007-09-20 5:39 am
回答 (1)
2007-09-20 5:44 am
✔ 最佳答案
Time spent from A to B = 10/2 s = 5 sTime spent from B to A = 10/3 s = 3.33 s
total time of journey = (5 + 3.33) s = 8.33 s
Total distance covered = (10+10) m = 20 m
hence, average speed = distance/time = 20/8.33 m/s = 2.4 m/s
收錄日期: 2021-04-29 17:24:22
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