题干

如图所示,一水平方向足够长的传送带以vl=1m/s的速度沿顺时针方向运动,传送带右端有一与传送带等高的光滑水平面.物块以v2=2m/s的速度水平向左滑上传送带后,对物块的运动,下列判断正确的是(   )

A:最终从传送带左端滑落

B:将以1m/s的速度返回光滑水平面

C:先向左匀减速后向右一直匀加速并回到光滑水平面

D:若增大vl,物块向左运动的位移将减小

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答案(点此获取答案解析)

B

同类题1

阅读下面短文, 从短文后各题所给的四个选项(A、B、C、D)中, 选出可以填入空白处的最佳选项。
    As children, our parents had dreams for us. They wanted us to do whatever was necessary to reach our highest 1. Later in life, friends and spouses (配偶) may also have schedules for us. People close to us may have ideas about 2we should live our lives. The ideas usually 3love and the desire for us to be happy. Other times, they come from a place of need within them— 4it is the parent who wants us to 5his or her dreams or the friend who wants us to play an already­defined role. We can appreciate and consider those people's input, but 6we must follow our own inner guidance.
    There may come a time when all the suggestions can become  7. We may feel that the people we love don't approve of our judgment, which can 8us to some extent. It can 9the choices we make for our lives by making us 10ourselves. It may also fill a void (空虚) with their 11before we've had a chance to decide what we want. However, it can affect us 12as well. We may have to 13the feelings of resistance and to keep ourselves off from them. But we can take some time to 14ourselves of any unnecessary doubts and go within to become 15on what we desire for ourselves.
    We can tell our loved ones how much we 16their thoughts and ideas, but that we need to live our own lives and make our own  17. We can explain that they need to let us learn from our own experiences 18 to rob us of wonderful life lessons and the opportunity to  19our own judgment. When they see that we are happy with our lives, they can see all we need them do is to share 20with us.