把20km/h 轉做 m/s ??把46m/s 轉做 km/h ??

20km X 1000m/1km = 20000m
1h X 60min/1h X 60s/1min = 3600s
20km/h = 20000m/3600s = 5.56m/s (cor. to 3 sig. fig.)

46m / 1000m x 1km = 0.046km
1s / 60sX1min / 60minX1h = 0.000277...
46m/s = 0.046km/0.0002778h = 166km/h (cor. to 3 sig.fig.)

2007-04-06 15:42:05 補充：
that was the theoratical calculation, for instance, you can look at the simpler method(i) o係一個鐘裏面行左20公里(20km) X 1000, 亦即係20000米(20000m)要轉番做秒既話就要將1h X 60 = 60分鐘, 再將60分鐘 X 60 = 3600秒(3600s)therefore: o係3600秒裏面行左20000米, 用計數機就即係5.56m/s

2007-04-06 15:42:25 補充：
(ii) 同樣既道理,不過掉番轉黎計o係一秒裏面行左46米(46m) / 1000, 亦即係0.046米(0.046m)要轉番做鐘頭既話就要將1s / 60 = 0.01667分鐘, 再將0.01667分鐘 / 60 = 0.000278個鐘(0.0002778h)therefore: o係0.0002778個鐘裏面行左0.046米, 用計數機就即係166km/h

2007-04-06 15:42:37 補充：
(ii) 又或者: 46m/s, 一個鐘就行左165600m/h (46m/s X 60分鐘 X 60鐘頭)要轉番做1km行幾遠就除番1000米, 即係165.6km/h (165600米 / 1000公里/米)

2007-04-06 15:44:30 補充：
第三個先係最易明同最簡單同最realistic,不過你tai完係應該明上面講d meh架喇希望幫到你啦