题干

如图所示,在O点放置正点电荷Q,a、b两点的连线过O点,且Oa=ab,以下说法正确的是(   )

A:将质子从a点由静止释放,质子向b做匀加速运动

B:将质子从a点由静止释放,质子运动到b的速率为v,则将α粒子从a点由静止释放后运动到b点的速率为 22 v

C:若电子以Oa为半径绕O做匀速圆周运动的线速度为v,则电子以Ob为半径绕O做匀速圆周运动的线速度为2v

D:若电子以Oa为半径绕O做匀速圆周运动的线速度为v,则电子以Ob为半径绕O做匀速圆周运动的线速度为 v2

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B

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    I received a devastating(毁灭性的)blow to my self-confidence in the first interview of my college years. I1to be a host in our Student Acting Troupe and felt 2 that I would be accepted. But one of the panel members told me, “You seem inadequate and you are a little vertically(垂直地)challenged.” My life has never been3 since. I used high heels to make up for my4and psychological strategies and tricks to5 my lack of confidence. But no matter how hard I tried to6 the part, there was still something 7.

    As president of English Club, I organized the rehearsal of Snow White and the Seven Dwarfs for an English party8 we could not find an actor to be the dwarf. It had to be someone who was humorous9and fluent in English. Suddenly, all eyes turned to me, and I knew I would have to be dwarf. To my surprise and delight, once 10I was totally11 in the performance and my humorous nature was put to full use. As the dwarf, I was a big12.

    Yes, each of us is only one among millions of people, but each of us is an individual and each of us is 13 Cultivating(培养)our individuality will 14 our life, making it a kaleidoscope(万花筒)of new colors and textures.

    A world lacking 15would be a boring place. The real16 is not being short or shy or ugly, but having your17 lost in a world in which everyone is a (n)18 of a model, a cool boy or a flawless charming girl.

    Given a choice, I would rather be19than live in such a world. I'd rather be a genuine dwarf accompanying a Snow White than be a Snow White among nothing but Snow Whites. I would rather be myself. I would20 my individual and unique colors to the more diverse universe. Please, be yourself!