题干

物体从某一高处自由落下,落到直立于地面的轻弹簧上,如图所示.在A点物体开始与弹簧接触,到B点物体的速度为0,然后被弹簧弹回.下列说法中正确的是(  )

A:物体从A下落到B的过程中,受到弹簧的弹力不断减小

B:物体从A下落到B的过程中,速度越来越小

C:物体从B上升到A的过程中,受到弹簧的弹力不断减小

D:物体从B上升到A的过程中,速度越来越大

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答案(点此获取答案解析)

C

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    On August 26,1999,New York City experienced a torrential downpour.The rain caused the streets to1and the subway system almost came to a stop.

    Unfortunately, this happened during the morning rush hour.Many people who were going to work were2to go home.Some battled to3a taxi or to get on a bus.Still others faced the4bravely,walking miles to get to work.

    I 5 to be one of the people on the way to work that morning.I went from subway line to subway line only to find that most6had stopped.After making my way7crowds of people,I finally found a subway line that was 8.Unfortunately,there were so many people waiting to9the subway that I could not even get down the stairs to the10.So I took the train going in the opposite direction,and then switch back to the downtown train.Finally,after what seemed like an forever,the train11my stop.Then I had to walk several blocks in the increasingly heavy rain. When I finally got to my office,I was12through,exhausted and13.

    My co-workers and I spent most of the day drying off.When it was 5:00 pm,I was ready to go home.I was about to turn off my computer14I received an email from Garth,my Director:

    I would like to thank all of you who made the effort and15reported to work.It is always reassuring(今人欣慰),at times like these,when employees so clearly show their16to their jobs.Thank you.

    Garth's email was short, but I learned more from that17message than I ever did from a textbook.The email taught me that a few words of18can make a big difference.The rainstorm and the traffic19had made me tired and upset.But Garth's words immediately20me and put a smile back on my face.