如图所示,一根跨越一固定水平光滑细杆的轻绳两端拴有两个质量均为m的小球a和b(可

题型:计算题

问题:

如图所示,一根跨越一固定水平光滑细杆的轻绳两端拴有两个质量均为m的小球a和b(可视为质点), Oa段的长度为L1,Ob段的长度为L2,且L1>L2,球a置于地面,球b被拉到与细杆同一水平的位置,在绳刚拉直时放手,小球b从静止状态向下摆动,当球b摆到最低点时,恰好与球a在同一水平位置发生碰撞并粘合在一起,设碰撞时间极短,往后两球以O点为圆心做圆周运动,若已知碰前瞬间球a的速度大小为va,方向竖直向上,轻绳不可伸长且始终处于绷紧状态,(已知a,b质量相同)求:

(1)球b在碰撞前瞬间的速度大小;

(2)两小球粘合后将做圆周运动时绳中张力的大小。

考点:机械能守恒定律向心力碰撞
题型:计算题

不同元素本质的区别是原子的(  )

A.电子数不同

B.中子数不同

C.质子数不同

D.最外层电子数不同

题型:计算题

Я справился с этой работой только ______ вашей помощи.

A.из-за

B. благодаря

C.от

D.по

题型:计算题

定子绕组串电阻的降压启动是指电动机启动时,把电阻串接在电动机定子绕组与电源之间,通过电阻的()作用来降低定子绕组上的启动电压。

A、分流

B、压降

C、分压

D、分压、分流

题型:计算题

I used to find notes left in the collection basket of the church, beautiful notes about my homilies(讲道)and about the writer’s thoughts on the daily readings. The (1) fascinated me. But it was a long time (2) I met the author of the notes.

One Sunday morning, I was (3) that someone was waiting for me in the office, a young woman who said she (4) all the notes. When I saw her I was (5) , since I had no idea thatit was she who wrote the notes. She was sitting in a chair in the office. Her (6) was bowed and when she raised it to look at me, she could barely (7) without pain. Her face was disfigured(畸形), so smiling was very (8) for her. We (9) for a while that Sunday morning and agreed to meet for lunch later that week. As it (10) , we went to lunch several times, and we shared things about our (11) . We spoke of authors we both had (12) , and it was easy to tell that (13) are a great love of hers. She suffered from a disfigurement that cannot be made to look (14) . I know that her condition (15) her deeply. Yet there was a beauty to her that had nothing to do with (16) . She was one to be listened to, whose words came from a wounded but (17) heart. She possessed a fine tuned sense of beauty. Her only (18) in life was the loss of a friend. The truth of her life was a desire to see beyond the (19) for a glimpse of what it is that matters. She found beauty and (20) and they befriended her, and showed her what is real.

13().

A.friends

B.churches

C.writings

D.books

题型:计算题

下列选项中,可以转让的债权是( )。

A.扶养费支付请求权

B.属于从权利的债权

C.演出公司对演员享有的债权

D.基于买卖合同享有的债权

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