F浮＝F空气－F液＝4.47-4.11=0.36NG铁=p铁gV铁铁＝G物/p铁·g＝4.47/7900*10=5.66x10^-5F浮＝p液gVp液＝F浮/gV=0.36/5.66x10^-5x10=0.64x10^3kg/m^3
