2) A man jogs towards the north for one hour, then towards the east for 30minutes and finally towards the south for 45minutes. If the distances he travels are 8km,4km and 5km respectively,
(a) what is the average speed of the man?
(b)what is the average velocity of the man?
10分 physics 快!!!
2007-10-16 2:47 am
回答 (2)
2007-10-16 2:54 am
✔ 最佳答案
2.a. Total distance travelled= 8 + 4 + 5
= 17 km
Total time required
= 1 + 0.5 + 0.75
= 2.25 h
So, average speed of the man
= Distance / time
= 17 / 2.25
= 7.56 km/h
= 7.56 X 1000 / 3600
= 2.10 m/s
b. By pythragus theorem,
total displacement travelled
= [4^2 + (8 - 5)^2]^1/2
= 5 km
So, average velocity
= displacement / time
= 5 / 2.25
= 2.22 km/h
= 2.22 X 1000 / 3600
= 0.617 m/s
參考: Myself~~~
2007-10-16 2:50 am
a. 8km/hr
收錄日期: 2021-04-13 13:56:00
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