• 2021-04-14
    截面杆AD受集中力作用,如图所示。设NAB、NBC、NCD分别表示该杆AB段,BC段和CD段的轴力,则下列结论中哪些是正确的?( )http://image.zhihuishu.com/zhs/onlineexam/ueditor/201808/0a0544d1c8324487be361111f88a1331.png