<p>轴向受拉压杆横截面积为A，受荷载如图所示，则m-m截面上的正应力<img alt="" src="https://file.gaojiufeng.cn/learnAppQuestion/25/b0/25b02ec03029b401b5a1b62e8608d9e2.jpg" style="width: 100%;height: auto;">为： <img alt="" src="https://file.gaojiufeng.cn/learnAppQuestion/b9/a3/b9a374d530a078fab314c5db6f32f14d.jpg" style="width: 100%;height: auto;"><img alt="" src="https://file.gaojiufeng.cn/learnAppQuestion/c5/f5/c5f57a777dfa35eada92a229438aef78.jpg" style="width: 100%;height: auto;"></p>