一辆执勤的警车停在平直的公路旁,当警员发现有一辆违章的货车从他旁边以8m/s的速

题型:问答题

问题:

一辆执勤的警车停在平直的公路旁,当警员发现有一辆违章的货车从他旁边以8m/s的速度匀速经过时,立即上车追赶,当警车开动时,货车已经在前方20m处了,已知警车做匀加速直线运动,加速度大小为2m/s2,求:

(1)警车要多长时间才能追上货车?

(2)警车在追上货车之前,两车间的最大间距是多少?

考点:匀变速直线运动的速度与时间的关系匀变速直线运动的位移与时间的关系
题型:问答题

继发性红斑性肢痛症常由下面哪种疾病引起()

A.雷诺病

B.糖尿病

C.甲状腺功能亢进

D.真性红细胞增多症

E.皮肌炎

题型:问答题

一出血患者,PT(一期法)20s,加正常血浆为12s,凝血酶时间正常,最大可能诊断是()

A.纤维蛋白原缺乏症

B.第V因子缺乏症

C.凝血酶原缺乏症

D.第Ⅷ因子缺乏

E.第Ⅹ因子缺乏

题型:问答题

旋涡泵的流量用旁路调节。

题型:问答题

完成句子。

1. The pictures, ______________________ my happy childhood, were taken when I went camping

    with my classmates. (remind)  

    我和同学去露营时照了这些照片,它们使我想起了我快乐的童年.

2. A balanced diet is necessary and it is suggested by the doctors ______________________ on the

    food rich in fat and sugar. (cut)

健康的饮食是必要的,医生建议我们少吃高脂肪和高糖分的食物.

3. John didn't turn up yesterday. He ______________________ the meeting. (forget)

   约翰昨天没来.他一定是忘了那个会了.

4. The new bridge is designed to be ______________________ as the old one and will have been

    built by the end of 2012. (long)

   这座新桥的长度是旧桥的两倍,将要在2012年年底完工.

5. At present, some new equipment, as well as some new technologies from Canada, _________

    _____________ in the production process. (use)

   一些新的来自于加拿大的设备和技术正用于生产中.

6. Not until we watched the Earth Day program on TV ______________________ much about global

    warming. (learn)

   直到我们观看了地球日的电视节目,我们才了解了大量关于全球变暖的问题.

7. His ability has never been in doubt-the question is ______________________ . (chance)

   他的能力不容置疑--问题是他愿不愿意冒险.

8. ______________________ , there are many fans waiting to see her. (go)

   无论她到哪里,总有许多的粉丝等着见她.

9. __________________ 65 million years ago still remains a mystery. (disappear)

   恐龙(dinosaur)为什么会在六千五百万年前突然消失依然是个谜.

10. The boss asked me ______________________ the present situation, but there was really no

      quick answer to it. (deal)

     老板问我将如何应对目前的状况,我一时不知该如何回答.

题型:问答题

第三部门研究的一个核心课题是()

A、公共责任

B、公共利益

C、公共服务

D、公共道德

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