外径7.5mm壁厚0.45mm长750mm的铁管重量是多少

Question

外径7.5mm 壁厚0.45mm 长750mm 的铁管重量是多少

Answer 1

外径D=7.5mm=0.75cm,外半径R=0.75/2=0.375cm,
内径d=7.5-2*0.45=7.5-0.9=6.6mm=0.66cm,内半径r=0.33cm.
铁管的体积V=π(R^2-r^2)*L=π*(R+r)(R-r)*L.
V=3.14*(0.375+0.33)(0.375-0.33)*75.
=3.14*0.705*0.045.
=7.47(cm^3).
铁的比重γ=7.8克/立方厘米.
故,铁管的重量G=V*γ=7.47*7.8=58.28(克）---即为所求.