f.4 phys,,,mechanics,,
2008-09-26 5:01 am
Calculate the thinking distance, braking distance and hence the stopping distance of a car travelling at 100kmh^-1, assuming an average reaction time of 0.7s and a uniform decelaration of 5ms^-2.
回答 (1)
2008-09-26 5:09 am
✔ 最佳答案
Initial velocity, u = 100 kmh-1 = 27.78 ms-1Acceleration, a = -5 ms-2
Final velocity, v = 0
a. For the thinking distance, the car is moving at uniform velocity
Thinking distance, d = ut = (27.78)(0.7) = 19.44 m
b. By v2 = u2 + 2as
0 = (27.78)2 + 2(-5)s
Braking distance, s = 77.16 m
Stopping distance = d + s = 19.44 + 77.16 = 96.60 m
參考: Myself~~~
收錄日期: 2021-04-13 16:07:05
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080925000051KK01886