题干

如图所示为甲乙两质点作直线运动的速度—时间图象,则下列说法中正确的是(   )

A:甲质点在0 ~ t1时间内的平均速度小于乙质点在0~t2时间内平均速度

B:甲质点在0 ~ t1时间内的加速度与乙质点在t2~t3时间的加速度相同

C:在0 ~ t3时间内甲、乙两质点的平均速度相等

D:在t3时刻,甲、乙两质点都回到了出发点

上一题 下一题 0.0难度 选择题 更新时间:2016-12-01 03:11:21

答案(点此获取答案解析)

C

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    Have you ever noticed what happens to an idea once you express it? Just talking about it or writing it down causes you to make it clear in your own mind. How can you use this to increase your brain power? Start writing.

    By putting thoughts into words, you are telling yourself the logic(逻辑)behind what you think, feel, or only partly understand. Often, explaining a thought is the process of understanding. In other words, you increase your brain power by exercising your “explain power.”

    Try this experiment. Explain how you'll increase your brain power, even if you have no idea right now. Just start with anything, and create an explanation. For example, start with “I'll learn chess,” or “I'll read an article on the mind every week.” Explain how that will help. You'll be surprised how often this becomes a workable plan, and if you actually do this, you'll have a better understanding of your brain from now.

    Another benefit of writing is that it helps you remember. Many, if not most, highly productive people are always taking notes. You can try keeping it all in your head, but if you keep a journal of your ideas the next time you're working on a big project, you'll probably have more success.

    Want to understand a topic? Write a book about it. That's an extreme example, but if you are learning something new, write a letter to a friend about it, and you will understand it better. Want to invent something? Write an explanation of the problem, why you want to solve it, and why it is worth solving, and you're half-way there.

    Writers don't always write because they clearly understand something beforehand. Often, they write about something because they want to understand it. You can do the same. Writing will help bring you to an understanding. Give it a try.