某同学利用两个滑轮组装了一个滑轮组,将重为300N的物体从一楼匀速提升到三楼,所

题型:填空题

问题:

某同学利用两个滑轮组装了一个滑轮组,将重为300N的物体从一楼匀速提升到三楼,所用的拉力为120N,则该滑轮组的机械效率为____________

考点:滑轮(组)的机械效率
题型:填空题

Spelling.

1. She hadn't read the letter and so was unaware of its c______.

2. U______, my computer system broke down again.

3. He e______ us for hours with his stories and jokes.

4. You'll need to c______ them of your enthusiasm for the job.

5. Traffic is bad, p______ in the city centre.

6. The competition attracted over 5,000 athletes r______ 18 countries.

7. The school has decided to adopt a different a______ to discipline (纪律).

8. There must be some m______ - I thought I ordered the smaller model.

9. Despite the power cuts, the hospital continued to f______ normally.

10. Well, really and t______, things weren't quite how she described them.

题型:填空题

利用化合物能够形成氢键缔合的分离是()

A.吸附层析 

B.聚酰胺层析 

C.凝胶层析 

D.离子交换层析 

E.正相分配层析

题型:填空题

A是含C、H、O三种元素的有机物,如果已知下列相关物理量,则可以确定A的分子式:

(1)碳的质量分数ω(C)、(2)氢的质量分数ω(H)、(3)A的质量m(A)、(4)A蒸汽对H2的相对密度、

(5)A的体积V(A)。

下列选项中一定能确定A分子式的组合是 [ ]

A.(1)(2)(3)

B.(1)(2)(4)

C.(3)(4)(5)

D.(1)(3)(5)

题型:填空题

对于()等严重破坏社会秩序的犯罪分子,可以附加剥夺政治权利。

A、故意杀人

B、爆炸

C、投毒

D、抢夺

题型:填空题

负责在取得定点资格的医疗机构(零售药店)中确定定点医疗机构(零售药店)的是()

A.参保人员

B.统筹地区劳动和社会保障部门

C.统筹地区社会保险经办机构

D.统筹地区药品监督管理部门

E.统筹地区卫生行政部门

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