图示桁架结构杆①的轴力为:
(来学网)
  • A.
    (来学网)3P/4
  • B.
    (来学网)P/2
  • C.
    (来学网)0.707P
  • D.
    (来学网)1.414P
正确答案:
B
答案解析:
先判断零杆,再用截面法以A为矩心求N