Jawabanmu

2014-09-09T21:59:52+07:00
2014-09-09T22:02:49+07:00
T = 0,5 jam = 30 menit = 1800 sekon
s = 40 km⇒ 40000 m
kecepatan (v)?
v = s/t
v = 40000÷1800
v = 22,22 m/s