HKCEE 2001 PHYSICS PAPER 2
Q2.
Caution
please give me complete formula, OK??
A girl walks along a straight road from a point A to a point B with an average speed 1 ms-1. She then returns from B to A along the same road with an average speed 2 ms-1. Find the average speed of the girl for the whole journey.
A.zero
B.0.67 ms-1
C.1.33 ms-1
D.1.41 ms-1
E.1.50 ms-1
hi PS Ans me physics Q!!!
2009-05-17 1:36 am
回答 (1)
2009-05-17 2:08 am
✔ 最佳答案
Let d be the distance between A and B. t be the time required to travel from A to B, then t/2 is the time to travel from B to A.Speed = distance / time
So, 1 = d / t
t = d
Now, the total distance = 2d
And the total time = t + t/2 = 3t/2
So, the average speed
= total distance / total time
= 2d / (3t/2)
= 4d / 3d
= 4/3
= 1.33 ms-1
The answer is C.
參考: Physics king
收錄日期: 2021-04-19 14:21:51
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