If an equal-width running track around the park. Everyday, Charles runs in the track. His runnung speed is 5 km/h. It takes him 18 seconds more to finish running a round along the outer track than the inner track.
a) Find the running speed of Charles in m/s.
b) Find the difference of lengths of the outer track and the inner track.
c) Find the width of the running track.
Rate (2)
2007-02-10 8:24 pm
回答 (1)
2007-02-10 8:36 pm
✔ 最佳答案
(A)the running speed of Charles
=5 km/h
=5000m/3600s
=1.389m/s
(b)
the difference of lengths of the outer track and the inner track
=1.389*18
=25 m
(c)
So the difference of lengths of the outer track and the inner track
=2pi(r1-r2)
2pi(r1-r2)=25
r1-r2=3.979
the width of the running track is 3.979 m
2007-02-10 12:38:49 補充：
r1 radius of outer track r2 radius of inner track
收錄日期: 2021-04-25 16:52:52
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070210000051KK01531