现代宇宙学告诉我们,恒星在演变过程中,会形成一种密度很大的天体,成为白矮星或中子

题型:问答题

问题:

现代宇宙学告诉我们,恒星在演变过程中,会形成一种密度很大的天体,成为白矮星或中子星,1m3的中子星物质的质量为1.5×1017kg,绕此中子星运行的卫星的最小周期为多少?(G=6.67×10-11 N•m2/kg2,球的体积v=

4
3
πR3)若某一中子星半径为10km,求此中子星的第一宇宙速度.

考点:万有引力定律的其他应用
题型:问答题

如图14-4-3所示为两条电阻丝的U-I图线,甲、乙图线与横坐标轴的夹角分别为α、β,当两条电阻丝加以相同的电压时,其功率之比P∶P为( )

图14-4-3

A.tanα∶tanβ

B.tanβ∶tanα

C.tanα∶tanβ

D.tanβ∶tanα

题型:问答题

When I was eight, I saw a movie about an island that had an erupting volcano and jungles filled with wild animals.The island was ruled by a beautiful woman called Tondalaya, the Fire Goddess of the Volcano.It was a low budget movie, but to me, it represented the perfect life.But through the years, Tondalaya was forgotten.

The week I turned 50, my marriage came to a sudden end.My house, furniture and everything I'd owned was sold to pay debts that I didn't even know existed.In a week I had lost my husband, my home and my parents who had refused to accept a divorce in the family.

I'd lost everything except my four teenage children.I used every penny I had to buy five plane tickets from Missouri to Hawaii.Everyone said I was crazy to think I could just run off to an island and survive.I was afraid they were right.

I worked 18 hours a day and lost 30 pounds because I lived on one meal a day.One night as I walked alone on the beach, I saw the red orange lava(火山岩) pouring out of Kilauea Volcano in the distance.It was time to live my imagination!

The next day, I quit my job, bought some art supplies and began doing what I loved.I hadn't painted a picture in 15 years.I wondered if 1 could still paint.My hands trembled the first time I picked up a brush.But after an hour had passed, I was lost in the colors spreading across the canvas(画布) in front of me.And as soon as I started believing in myself, other people started believing in me, too.The first painting sold for $ 1500.

The past six years have been filled with adventures.My children and I have gone swimming with dolphins, watched whales and hiked around the crater rim (火山口边缘) of the volcano.We wake up every morning with the ocean in front of us and the volcano behind us.

The dream I had more than 40 years ago is now reality.I'm living freely and happily ever after.

小题1:Why did the writer go to Hawaii?

A.To make a living.

B.To spend her holiday.

C.To free herself from trouble.

D.To realize her childhood dream.小题2:Which of the following is the writer's dream?

A.Get close to wildlife.

B.Live a free and happy life.

C.Live in nature with animals.

D.Become a successful painter.小题3:We can infer from the passage that _____.

A.the writer had never done painting before

B.the writer's parents encouraged her to divorce

C.the writer's husband took away most of her money

D.the writer wasn't sure whether she could survive in Hawaii at first

题型:问答题

某实验小组用同一把最小分度值为厘米的刻度尺测量同一物体的长度,在下列记录的数据中正确的是(  )

A.6.2分米

B.62厘米

C.6.20分米

D.620.0毫米

题型:问答题

下列机械密封的性能中不属于密封件的综合性能是()。

A、密封性能

B、安装性能

C、摩擦性能

D、耐压性能

题型:问答题

建设工程监理招标与投标

某工程,实施过程中发生如下事件:

事件1:总监理工程师对项目监理机构的部分工作做出如下安排:

(1)总监理工程师代表负责审批监理实施细则,进行监理人员的绩效考核,调配监理人员;

(2)专业监理工程师全权处理合同争议和工程索赔。

事件2:施工单位向项目监理机构提交了分包单位资格报审材料,包括营业执照、

分包单位业绩。项目监理机构审核时发现,分包单位资格报审材料不全,要求施工单位补充提交相应材料。

事件3:深基坑分项工程施工前,施工单位项目经理审查该分项工程的专项施工

方案后,即向项目监理机构报送,在项目监理机构审批该方案过程中就组织队伍进场

施工,并安排质量员兼任安全生产管理员对现场施工安全进行监督。

事件4:项目监理机构在整理归档监理文件资料时,总监理工程师要求将需要归

档的监理文件直接移交本监理单位和城建档案管理机构保存。

事件4中,指出总监理工程师对监理文件归档要求的不妥之处,写出正确做法。

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