题干

如图所示,在水平圆盘上沿半径方向放置用细线相连的质量均为m的A、B两个物块(可视为质点).A和B距轴心O的距离分别为rA=R,rB=2R,且A、B与转盘之间的最大静摩擦力都是fm,两物块A和B随着圆盘转动时,始终与圆盘保持相对静止.则在圆盘转动的角速度从0缓慢增大的过程中,下列说法正确的是(   )

A:B所受合外力一直等于A所受合外力

B:A受到的摩擦力一直指向圆心

C:B受到的摩擦力一直指向圆心

D:A,B两物块与圆盘保持相对静止的最大角速度为 2fmmR

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答案(点此获取答案解析)

C,D

同类题1

阅读短文,从每题所给的四个选项(A、B、C 和 D)中选出最佳选项。

B

Welcome to English First, a teaching experience you will never forget!

    We're looking for amazing English teachers to join us in Beijing, Shanghai, Shenzhen, Guangzhou, and many other cities across China to teach adults, children or at our online     schools. You will get a good pay.

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    English First is the world's best education company. Set up in 1965, EF runs in over 50 countries around the world. We still need teachers for teaching jobs across China, so if you  like modern city life, we probably have what you want. We  have both Teens  schools and Adult schools in over 60 cities in China.

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    At English First, we'll offer you the best teaching ways to help you become the best teacher. Our new and colorful classrooms provide you with great teaching tools, including computers and iPads. We also offer the best teacher development program for our teachers.

Join the EF Teacher Network Today

    We're here to provide what we need for every step of the way, from preparing your work visa to the airport pickup service. Learn how to order food in Chinese during our free language classes. There're many new experiences of living abroad "waiting" for you to have here. And you'll experience them to the fullest at EF.

What you should be (what you need)for the job

★A native English speaker.

★Having a four-year learning experience at university.

★The Teaching English as a Foreign Language(TEFL)paper.

★A passport holder from the western country.

★The ability to live abroad for at least one year.