Jawabanmu

2014-03-29T05:36:29+07:00
D = 1/2 v.t
210 = 1/2 1400.t
210 = 700.t
210/700 = t
0,3 = t
2014-03-29T06:03:44+07:00
S = 210 m V = 1400 m/s T ....? 2s = v.t 420 = 1400 x t T = 1400 / 420 = 3,4 s