如图(甲)所示,一对足够长平行光滑轨道放置在水平面上,两轨道间距l=0.5m,左

题型:计算题

问题:

如图(甲)所示,一对足够长平行光滑轨道放置在水平面上,两轨道间距l=0.5m,左侧接一阻值为R=1的电阻;有一金属棒静止地放在轨道上,与两轨道垂直,金属棒及轨道的电阻皆可忽略不计,整个装置处于垂直轨道平面竖直向下的匀强磁场中。t=0时,用一外力F沿轨道方向拉金属棒,使棒以加速度a=0.2 m/s2做匀加速运动,外力F与时间t的关系如图(乙)所示。

(1)求金属棒的质量m

(2)求磁感强度B

(3)当力F达到某一值时,保持F不再变化,金属棒继续运动3秒钟,速度达到1.6m/s且不再变化,测得在这3秒内金属棒的位移s=4.7m,求这段时间内电阻R消耗的电能。

考点:电磁感应现象的综合应用
题型:计算题

下列各句中,熟语使用正确的一项是(   )(3分)

A.按照上级部署,深圳市对口援助四川地震灾区德阳市。深圳市政府表示,对德阳市人民遇到的困难,我们将鼎力相助。

B.现在是高考冲刺的黄金时段,我们每位同学都要利用好每一分钟,等到高考结束后再做事后诸葛亮,后悔可就晚了。

C.在纪念改革开放三十年的日子里,我们永远也不会忘记那些为我国的经济发展处心积虑、日夜操劳、鞠躬尽瘁的人。

D.在某些经济发达的沿海城市,黄赌毒泛滥成灾,但相关的职能部门却不闻不问、泰然处之、无所作为,这难道不奇怪吗?

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当前实施素质教育应该以培养学生的______和社会实践能力为重点。

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Dear Teresa Silva,

The official of the university has reported to us that you are an English major who meets the high standards for membership in Sigma Tau Delta. As is known, Sigma Tau Delta was founded in 1924 at Dakota Wesleyan University. It is an international collegiate honor society for students of English. It presently has over 850 chapters in the United States, Europe, the Middle East, and the Caribbean. Over 9,000 new members are admitted into the organization annually.

Sigma Tau Delta’s purpose is to promote literature and writing and to advance the study of the written word. Members gather annually in the spring at the international meeting to present papers and share experiences and ideas within the English subject. The Society offers tens of thousands of dollars in scholarships, awards, as well as publication chances in its journals The Rectangle and The Sigma Tau Delta Review.

It is our pleasure if you can complete the application for Sigma Tau Delta membership. If you would like to be included in this spring’s induction (入会) ceremony, please complete the application form, and include amount to cover both local and international fees. Your completed form must be received by date to be considered for the upcoming induction ceremony.

We congratulate you on your outstanding academic record and hope you will join us as a Sigma Tau Delta member. If you want to get more information, please visit our website www.sigmataudelta.org, or give us a call. The phone number is 583-2864.

Sincerely,

Emily Lister

小题1:According to the passage, Sigma Tau Delta ______.

A.deals with language learning

B.opens its door to all the students of English

C.changes its members every year

D.mainly takes charge of scientific publications小题2:At the annual meeting, members of Sigma Tau Delta have the chance to ______.

A.meet all the chapter leaders

B.receive tens of thousands of dollars

C.share experiences and views

D.choose a particular subject as a major小题3:This passage is basically a letter of _____.

A.introduction

B.congratulation

C.thanks

D.invitation

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下列哪一种方法不能除去药液中热原

A.活性炭吸附法

B.离子交换法

C.微滤法

D.反渗透法

E.凝胶滤过法

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对于一张工作票中既有小修又有试验等列入计划的工作内容一停多用的情况,按“()、()、()、()、()”的顺序填报一项。

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