Jawabanmu

2014-02-05T16:51:57+07:00
A (percepatan planet lama) = F/m
  =30N/ 4kg
 = 7,5 m/s2

a (percepatan gravitasi planet baru) 1/3 x 7,5 m/s2
= 3m/s2
F (gaya / berat) = m x a
  = 30 kg x 3m/s2
  = 90 N
m (massa) = F/a
               = 90 N/ 3 m/s2
               = 30 kg
^^
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