题目2单选题
如图所示的杆件,全长为2L,断面积分别为A及2A,弹性系数为E,求杆件在受到两个P力之作用后的总缩短量?<img src="https://p.ananas.chaoxing.com/star3/origin/bc63edfa1654a0afa46d5c1d73a64031.png">A. <img src="https://p.ananas.chaoxing.com/star3/origin/fbd66a47a160f369afe1b5532334874c.png">B. <img src="https://p.ananas.chaoxing.com/star3/origin/f0a1baa308694047e2b6fc113dff963a.png">C. <img src="https://p.ananas.chaoxing.com/star3/origin/ec18a7bd6d0331f30b97c4cad6f015e9.png">D. <img src="https://p.ananas.chaoxing.com/star3/origin/5240159ac5dc81d4fac8632f7d3b59a2.png">