题干

如图所示两辆质量相同的小车静止于光滑的水平面上,有一人静止在小车A上.当这个人从A车上跳到B车上,接着又从B车跳回并与A车保持相对静止时,A车的速率(    )

A:等于零

B:小于B车速率

C:大于B车速率

D:等于B车速率

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B

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    “How’s it going? ”  I ask the barista(服务生). “How’s your day been?”

    “Ah, not too busy. What are you up to?”

    “Not much. Just reading. ”

    This,small talk, is one of the key rituals(规矩)of American life. It has taken me only a decade to master.

    I immigrated to the United States in 2001, for college. I brought only my Indian experience in dealing with shopkeepers and tea sellers. In Delhi, where I grew up, when doing business, people don't ask each other how the other's day has been. They might not even smile. The customer doesn't tremble before complaining about how cold his food is. Each side believes the other will cheat him.

    “God, Mahajan, you’re so rude to waiters!” Tom, an American friend, said, laughing, after he watched me ordering food at a restaurant, in the West Village, years ago. Considering myself a mild and friendly person, I was surprised. Tom always asked servers how they were doing or praised their shirts or made jokes about the menu. At that time, this seemed dishonest to me. Did he really like what they were wearing?

    American life is based on a principle that we like one another but won’t violate one another’s privacies. This makes it a land of small talk. Two people greet each other happily, with friendliness, but might know each other for years before asking basic questions about each other’s backgrounds. The opposite is true of Indians. At least three people I’ve sat next to on planes to and from India have asked me, within minutes, how much I earn as a writer (only to turn away in disappointment when I tell them).

    Living in Brooklyn and then in Austin, Texas. I made coffee shops the places of my movements. Meeting the same baristas day after day produced context, and I got practice. I was beginning to fit in. It felt good and didn’t seem fake anymore.