皮皮学，免费搜题
登录
搜题
【简答题】
塔式起重机的结构简图如下图所示。设机架重力G=500kN，重心在C点，与右轨相距a= 5m。最大起吊重量P=250kN，与右轨B最远距离L=10m。平衡物重力为G1，与左轨A相距x=6m，二轨相距b=3m。试求起重机在满载与空载时都不至翻倒的平衡重物G1的范围和反力FNA (FNB)。 要保障满载时机身平衡而不向右翻倒，G1的最小值是( )。（单选） A.361kN B.361N C.375kN D.375N 要保障空载时机身平衡而不向左翻倒，G1的最大值是( )。（单选） A.361kN B.361N C.375kN D.375N 要保障满载时机身平衡而不向右翻倒，A点反力FNA应大于( )。（单选） A.O B.361N C.375kN D.375N 要保障空载时机身平衡而不向左翻倒，B点反力RJB应大于( )。（单选） A.361kN B.361N C.0 D.375N 若实际取用重为350kN的平衡物，为保障满载时机身平衡而不向右翻倒，可将平衡物远离支架以适当加大图示z的值。( )判断题
手机使用
分享
复制链接
新浪微博
分享QQ
微信扫一扫
反馈参考答案：
举一反三
【简答题】The job pays well and you get a 20 day holiday a year, it ’ s certainly an ____offer.A. attractive B. attract C. attracting D. attracted B. attract C. attracting D. attracted
【单选题】关于补体系统的叙述下列不正确的是?
A.
补体成分大多数以非活性的酶前体存在于血清中
B.
补体系统激活的三条途径均是酶的级联反应
C.
补体系统在非特异性免疫和特异性免疫中发挥作用
D.
补体系统的激活具有放大效应
E.
激活的补体只具有病理作用
【单选题】—May I ask you _____ the writer? —Sorry. I don’t know him. You can ask Sam ______ help.
A.
about; for
B.
about; about
C.
for; for
D.
for; about
【多选题】陪同来宾，应该注意以下哪些事项？（）
A.
随行人员走在客人和主陪人员的前面
B.
遇到路口或转弯处，接待人员用手示意或加以提示
C.
公务活动中，接待员在客人的左侧步行
D.
乘车时，陪同人员先上车，然后客人上车
【单选题】听力原文：Student: Good morning. Is that Copewell Insurance? I'd like to ask you a few questions about getting insurance. Salesman: Certainly. What kind of insurance are you looking for? Student: Well, I'm...
A.
are often at classes.
B.
often have high-value, portable items.
C.
are wealthier than other young people.
D.
don't usually lock campus accommodation.
【简答题】The job pays well and you get a 20-day holiday a year. It ’ s certainly an (attract) offer.
【单选题】The job pays well and you get a 20 day holiday a year ,it is certainly an__ offer.
A.
Attractive.
B.
Attract
C.
Attracting
D.
Attracted.
【简答题】The job pays well and you get a 20-day holiday a year, it’s certainly an(attract) ____ offer.
【单选题】The job pays well and you get a 20 day holiday a year, it ’s certainly an offer.
A.
attractive
B.
attract
C.
attracting
D.
attracted
相关题目：
参考解析：
知识点：
题目纠错 0
发布
