(6.2)梁的剪力图如( )所示(5分)
(7.1)计算C 截面的弯矩为( )(3分)
MC=6kN∙m(上侧受拉)
MC=9kN∙m(上侧受拉)
MC=3kN∙m(上侧受拉)
MC=12kN∙m(上侧受拉)
(7.2)计算截面对中性轴的惯性矩,Iz=( )(3分)
58.32x106(mm4)
58.32x106(mm2)
28.64x106(mm4)
28.64x106(mm2)
(7.3)计算C 截面上K 点的正应力,σk =( )(4分)
6.17MPa(拉应力)
3.09MPa(拉应力)
5.35MPa(拉应力)
4.25MPa(拉应力)
(8.1)梁的最大弯矩值为( )(3分)
Mmax=72kN∙m
Mmax=24kN∙m
Mmax=36kN∙m
Mmax=160kN∙m
(8.2)抗弯截面系数Wz=( )(3分)
5.12x105(mm3)
3.0722x106(mm3)
5.12x106(mm4)
6.12x105(mm3)
(8.3)最大正应力σmax=( )(3分)
140.625MPa
70.31MPa
281.25MPa
100.25MPa
(8.4)将梁的最大正应力与许用应力比较,可知( )(1分)
杆件满足正应力强度条件
杆件不满足正应力强度条件
What is the main idea of this article ?________
It’s smart to eat foods with low calories and fat content.
You can eat well in fast-food restaurant
Fast food is always bad for you .
Fast-food restaurants are the best the place to find healthy foods .
A small hamburger and small firies has __________
more calories and fat than a chicken sandwich and a salad.
fewer calories and fat than a chicken sandwich and a salad.
the same amount of calories and fat as a chicken sandwich and a salad.
the same amount of calories and fat as a large portion of fries.