Jawabanmu

2014-05-30T15:15:18+07:00
V = s : t
v = 280 m : 0,4 s
v = 700 m/s
2014-05-30T15:41:27+07:00
V = s .t /2
v = 280 . 0,4 / 2
v = 112 / 2
v = 56