A car travels up a hill at constant speed of 4 m/s and returns down the hill at a constant speed of 6 m/s. Calculate the average speed for the round trip.
我唔記得左點計 average speed,
要有step, 我想明白點做 =)
希望大家可以幫幫忙啦!
Thank you very much!
Ans: 4.8 m/s
average speed - phy mechanics
2009-09-28 4:27 am
回答 (1)
2009-09-28 6:15 am
✔ 最佳答案
Let d be the distance between two places.In the first journey,
d = 4t1
t1 = d/4 ... (1)
In the second journey,
d = 6t2
t2 = d/6... (2)
The average speed
= Total distance / Time taken
= 2d / (t1 + t2)
= 2d / (d/4 + d/6)
= 2 / (1/4 + 1/6)
= 2(12) / (3 + 2)
= 4.8 m/s
參考: Physics king
收錄日期: 2021-04-19 15:26:40
原文連結 [永久失效]:
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