3． A 端是固定端，梁AB 的自重不计，试作出悬臂梁AB 的受力图。（5分）

<img src、"http://sichuan.ouchn.cn/pluginfile.php/56687/question/answer/371776/26/224059/01.png" alt="" width="355" height="136">

<img src、"http://sichuan.ouchn.cn/pluginfile.php/56687/question/answer/371776/26/224060/02.png" alt="" width="280" height="123">

<img src、"http://sichuan.ouchn.cn/pluginfile.php/56687/question/answer/371776/26/224061/03.png" alt="" width="343" height="138">

<img src、"http://sichuan.ouchn.cn/pluginfile.php/56687/question/answer/371776/26/224062/04.png" alt="" width="324" height="114">