题干

端午节赛龙舟时,如图所示,全体划桨手在鼓声的号令下有节奏地齐向后划水,龙舟就快速前进.则下列说法中正确的是(   )

A:浆对水的力小于水对浆的力

B:龙舟冲过终点后不能立即停下来是由于它具有惯性

C:龙舟冲过终点后减速滑行时所受力的合力为零

D:使龙舟快速前进的施力物体是浆

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答案(点此获取答案解析)

B

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    I' m ready to do my first jump 10 months after a skydiving (特技跳伞) accident. I can't wait! That accident almost killed me and it made me stay in hospital for half a year. During the boring long days, I didn't feel glad to be alive. I was wondering how I could live without my favorite sport.

    It all started one evening after a nine-to-five day. I was sitting on the sofa when an ad (广告) came on the television. "Try skydiving," it said. The next day, I went to the skydiving school in my town. At the end of the day's lessons, I knew I found the fight sport for me.

    I will never forget my first jump. Five of us walled to the runway and got into a plane. I was scared, but the others were tailing and joking, and I started to feel a little relaxed. It was a beautiful, cloudless day and the sun was just going down. Soon it was time to jump. As I jumped from the plane, I shouted. But then everything became quiet. It was the most wonderful four minutes of my life.

    From the first jump, I was hooked. I started spending all my free time skydiving . It became my reason for living. Things were going really well. Then an accident happened on my 104th jump. I broke my both legs, right arm and nose. I stayed in hospital for six months, but I still couldn't forget skydiving.

    My mother couldn't understand why the only reason I wanted to get better was to go skydiving again. But for me, skydiving is life, and life is skydiving.