$?解：(1) 設(shè)\rho ={\frac {k} {V}}$
$∵ 當(dāng)V=10m^3時，\rho =1.43kg/m^3$
$∴ 1.43={\frac {k} {10}}$
$解得，k=14.3$
$∴ 函數(shù)表達(dá)式為\rho ={\frac {14.3} {V}}$
$(2) 當(dāng)V=2m^3時，\rho ={\frac {14.3} {2}}=7.15(kg/m^3)$
$∴ 當(dāng)V=2m^3時氧氣的密度\rho為7.15kg/m^3$
