Jawabanmu

2014-06-03T00:06:42+07:00
Fa = Wu - Wc
     = 30 - 22
     = 8 N
Fa = Pc . Vbt . g
Fa = Pc .  \frac{m}{Pb} . g
8 = 1000 .  \frac{3}{Pb}  . 10
8Pb = 30000
Pb = 3750 kg/m^3