Jawabanmu

2014-06-24T21:14:20+07:00
V=108000/3600= 30m/s

W=ΔEk
W=(EK2-EK1)
W=1/2m(v2²-v1²)
W=1/2.4000(30²-0)
W=2000(900)
W=1800000Joule