如图示结构中,圆截面拉杆BD的直径为d,不计该杆的自重,则其横截面上的应力为()。
A.A
B.B
C.C
D.D
参考答案:B
解析:
[点评] 本题主要考察对轴心受拉杆件正应力的计算。
Each life preserver must be readily accessible to the person for whom it is intended while he or she is().
A.at work
B.in his or her berthing area
C.BOTH at work and in his or her berthing area
D.None of the above are correct
具有悬浮状、堆积状的可燃粉尘或纤维,虽不可能形成爆炸混合物,但在数量和配置上能引起火灾危险的环境被划为()。
A.10区
B.21区
C.22区