如图所示,水平放置的圆形线圈的半径为r,单位长度的质量为16 g,圆形线圈由三个

题型:计算题

问题:

如图所示,水平放置的圆形线圈的半径为r,单位长度的质量为16 g,圆形线圈由三个支撑点支撑处于静止。有一圆锥形磁场,线圈所处平面的磁感应强度为0.8T,锥形的顶角为60°,当线圈通以图示方向1.2A的电流时,线圈此时获得多大的加速度?(取g=10 m/s2

考点:牛顿运动定律的应用
题型:计算题

车轴负荷及轴重的标准是怎样规定的?

题型:计算题

关于进行性多灶性白质脑病叙述错误的是()

A.大多数病例由 * * 多瘤空泡病毒JC亚型引起,少数由SV-40亚型引起

B.临床表现与病变部位和数量有关

C.主要表现为皮质下白质的亚急性脱髓鞘

D.脑神经麻痹、共济失调、脊髓病变较常见

E.缺乏有效的治疗方法,80%的患者于9个月内死亡

题型:计算题

A letter to Edward, a columnist(报刊专栏作家)

Dear Mr Expert:

I grew up in an unhappy and abusive home. I always promised myself that I’d get out as soon as possible. Now, at age 20, I have a good job and a nice house, and I’m really proud of the independence I’ve achieved.

Here’s the problem: several of my friends who still live with their parents wish they had places like mine — so much so that they make mine theirs.

It started out with a couple of them spending the weekends with me. But now they seem to take it for granted that they can show up any time they like. They bring boyfriends over, talk on the phone and stay out forever.

I enjoy having my friends here sometimes — it makes the place feel comfortable and warm— but this is my home, not a party house. I was old enough to move out on my own, so why can’t I seem to ask my friends to respect my privacy(隐私)?

Joan

Edward’s reply to Joan

Dear Joan:

If your family didn’t pay attention to your needs when you were a child, you probably have trouble letting others know your needs now.

And if you’ve gathered your friends around you to rebuild a happy family atmosphere(气氛),you may fear that saying no will bring back the kind of conflict you grew up with— or destroy the nice atmosphere you now enjoy. You need to understand that in true friendship it’s okay to put your own needs first from time to time.

Be clear about the message you want to send. For example, “I really love your company but I also need some privacy. So please call before you come over.”

63. We can learn from the first letter that Joan Edward        .

A. lives away from her parents

B. takes pride in her friends

C. knows Mr Expert quite well

D. hates her parents very much

64. We can infer from the first letter that        .

A. Joan considers her friends more important than her privacy

B. Joan’s friends visit her more often than she can accept

C. Joan doesn’t like the parties at all

D. Joan dislikes the boyfriends her friends bring over

65. According to Mr Expert, why can’t Joan tell her friends her feelings?

A. She is afraid of hurting her friends.

B. She does not understand true friendship.

C. Her family experience stops her from doing so.

D. She does not put her needs first.

66. The underlined word “conflict” in the second letter means      .

A. dependent life    B. fierce fight C. bad manners      D. painful feeling

67. The second letter suggests that Mr Expert        .

A. is worried about Joan’s problem      B. warns Joan not to quarrel with her friends

C. advises Joan on how to refuse people      D. encourages Joan to be brave enough

题型:计算题

随着海洋资源的开发水深不断加深,浮式海洋平台越来越受到关注,下列平台属于浮式平台的是()。

A、半潜式平台

B、重力式平台(GBS)

C、导管架平台

D、自升式平台

题型:计算题

生态系统具有一种内部的自动调节能力,以保持自己的稳定性这种调节能力有赖于()

A.成分的多样性

B.能量流动的复杂性

C.物质循环途径的复杂性

更多题库