Jawabanmu

2014-03-02T13:41:50+07:00
40 x 3600 = 144.000m/jam
144.000 : 1000 = 144 km/jam (c)
2014-03-02T13:44:00+07:00
1 m = 10^-3 km
1 s =1/3600 jam

1 m/s = 3600/1000=3,6

40 m/s = 40*3,6 = 144 km/jam