一道初二物理题
\u521d\u4e8c\u7269\u7406\uff0c\u7b2c1\u9898\u3002\u8c22\u8c22\u6211\u8ba4\u4e3a\u662fc,\u50cf\u8ddd\u5927\u4e8e\u4e00\u500d\u7126\u8ddd\u6210\u5012\u7acb\u653e\u5927\u7684\u5b9e\u50cf
\u7b54\u6848\uff1a
\u4e8c\u529b\u5e73\u8861\uff1b
20
4\u00d710^8
\u4e0d\u660e\u8ffd\u95ee\u3002
即： 27N= 1×10^3kg/m^3 × 10N/kg ×（V球*3/4）
所以，V球=3.6×10^(-3) m^3
将中空部分装满某液体后，
球重 = ρ水×g×V排~ = ρ水×g×V球 =4/3*空心球重=36N
又 球重=铝重+液体重 所以，液体重=36-27=9N
V液=V球-V铝
V铝=27N÷10N/kg÷2.7×10^3kg/m^3=10^(-3) m^3
所以，V液=V球-V铝=2.6×10^(-3) m^3
所以，密度=9N÷10N/kg÷2.6×10^(-3) m^3=0.346×10^3kg/m^3
球有1/4体积露出水面,其等效密度0.75g/cm^3
V=2700/0.75=3600cm^3
空心部分的体积
V空=3600-1000=2600cm^3
液体的密度
3600/4/2600=0.346g/cm^3
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