如图所示,两平行导轨间距L=0.5m,足够长光滑的倾斜部分和粗糙的水平部分圆滑连

题型:填空题

问题:

如图所示,两平行导轨间距L=0.5m,足够长光滑的倾斜部分和粗糙的水平部分圆滑连接,倾斜部分与水平面的夹角θ=30°,垂直斜面方向向上的匀强磁场磁感应强度B=1.0T,水平部分没有磁场,金属杆ab质量m=0.05kg,电阻r=0.2Ω,运动中与导轨始终接触良好,并且垂直于导轨.电阻R=0.8Ω,导轨电阻不计.当金属棒从斜面上距底面高h=1.0m以上的任何地方由静止释放后,在水平面上滑行的最大距离x=1.25m,取g=10m/s2,求:

(1)金属棒在斜面上的最大运动速度;

(2)金属棒与水平导轨间的动摩擦因素;

(3)若金属棒从高度h=1.0m处由静止释放,电阻R产生的热量.

考点:导体切割磁感线时的感应电动势
题型:填空题

某建筑公司与甲企业签订一份建筑承包合同,合同金额4800万元。施工期间,该建筑公司又将其中价值1750万元的安装工程分包给乙企业,并签订分包合同。该建筑公司此项业务应缴纳营业税()万元。

A、144

B、52.5

C、91.5

D、196.5

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B

On the last day of his life, my dog Otto spent that morning of spring napping in the garden. This was always one of his favorite things to do, even before the days when he was too old and too weak to get out of a car by himself.

I probably would have started crying over Otto right then, if my two other little dogs hadn't suddenly raced past. Larry, who was a puppy, got knocked into Otto, then licked Otto's ear, and that got Otto excited, and Otto barked and tried to stand up again, but it was hard for him.

Soon it was time for me to drive to see Steve, our vet.

When Steve gave Otto the first shot, it made him woozy (眩晕的). Otto wandered over to where Steve and I were sitting and settled down between us. He has always liked to touch everyone in his pack, if possible, while he sleeps.

After Steve gave him the last shot and Otto stopped breathing, he didn't look like Otto anymore. He looked like an old gray-brown piece of beat-up carpet, and I suddenly realized what bad shape he'd been in for a long, long time. I wondered if he'd been in much more pain than I knew. Wondering made me feel even worse.

The week after Otto died was not good. Every morning when I walked Larry and Sticky in the neighborhood, somebody would come up and say they had heard about Otto and they were sorry. They were all Otto's friends and some of them cried. Others, like Debbie who lives on my street, reminded me about how, even at the end. Otto would stand between her twins' stroller (婴儿车) and the street when the garbage truck went by. "Like it was his job to protect them," she marveled.

Otto has left us, but his memory lives on.

60. How did the author feel when Otto was napping in the garden?

A. She felt like crying.                      B. She thought life was beautiful.           C. She found spring was wonderful.            D. She was relieved.

61. According to the passage, how did the dog die?

A. He had an accident on the street.          B. He died naturally.                  C. He was made to die by a vet.                   D. He starved.

62. What can we know about Otto?

A. He was already too old to bark.                            B. He liked people to keep him company.     C. He died a very painful death.                       D. He was protected by the neighbours.

63. We can see from the passage that Sticky is a ______.

A. cat                 B. dog              C. child            D. Neighbour

题型:填空题

胃底食管静脉曲张破裂出血的治疗方法是()

A.三腔两囊管压迫

B.肝叶切除术

C.奥美拉唑静脉点滴

D.胃大部切除

E.高选择性迷走神经切断

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维系蛋白质二级结构的化学键是

A.氢键

B.疏水键

C.盐键

D.范德华力

E.肽键

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容积式压缩机可分为往复式压缩机和()。

A.透平压缩机

B.引射器

C.轴流压缩机

D.回转式压缩机

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