Jawabanmu

2014-01-26T18:42:22+07:00
Ek = 1/2 . m . v²
800 J = 1/2 . 4kg . v²
800 J = 2kg . v²
400 m²/s² = v²
20 m/s = v
Jawaban paling cerdas!
2014-01-26T18:43:52+07:00
Ek =  1 \\ 2 x m x  v^{2}
800 = 1/2 x 4 x  v^{2}
800 = 2 x  v^{2}
800/2 =  v^{2}
400 =  v^{2}
v =  \sqrt{400}
v = 20 m/s
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