• 2022-07-01
    已知环形截面外径为D,内径为d,则截面对形心的极惯性矩( )
    A: [img=124x69]18038d732bae7c7.png[/img]
    B: [img=132x73]18038d7335a7893.png[/img]
    C: [img=120x66]18038d7340cc081.png[/img]
    D: [img=125x70]18038d734b61324.png[/img]