Jawabanmu

2014-01-28T20:01:46+07:00
720 joule : 40 kg= 18 km
 \frac{1}{2} x 18= 9 km
Jawaban paling cerdas!
2014-01-28T20:01:52+07:00
Dik :
m= 40 kg
ek = 720 joule
v.. ?

ek = 1/2 . m v^2
720 joule = 1/2 . 40 kg . v^2
1440 joule = 40 kg.v^2
1440/40 = v^2
36 = v^2
sehingga v = 6 m/s :)
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