2) uu Y= (331)2×29×10-3 RT =1.4 8.31×273 3) Y=pu2=7.8×103×(5100)2 =2.03×1011N/m2 结束目录 u RT = m γ = (331)2×29×10-3 8.31×273 =1.4 u= Y ρ Y =ρu 2 = 7.8×103×(5100)2 = 2.03×1011N/m2 (2) (3) 结束 目录