设长度为l
m=250kg ρ=7.85kg/m3 h=0.375 S=0.375lmm2=3.75×10-5m2 h=400mm=0.4m
m=ρV=ρshl
l=m/ρsh h=250/(7.85×3.75×10-5×.04)=2.12×10∧7
设长度为l
m=250kg ρ=7.85kg/m3 h=0.375 S=0.375lmm2=3.75×10-5m2 h=400mm=0.4m
m=ρV=ρshl
l=m/ρsh h=250/(7.85×3.75×10-5×.04)=2.12×10∧7