题干

如图所示为质点做匀变速曲线运动轨迹的示意图,且质点运动到D点时速度方向与加速度方向恰好互相垂直,则质点从A点运动到E点的过程中,下列说法中正确的是(   )

A:质点从B到E的过程中加速度方向与速度方向的夹角先增大后减小

B:质点经过A点时的加速度方向与速度方向的夹角小于90°

C:质点经过C点的速率比D点的大

D:质点经过D点时的加速度比B点的大

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C

同类题3

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    Please sit down and enjoy your meal. Just don't talk about it.

    These are the requirements at a popular dining party that is known as "silent dinners". It encourages people who take part in the dining party not to speak for one to two hours and not to use electronic devices. Instead, the idea is to just on the food.

    "Silent dinner parties are fast growing," said Honi Ryan, who has hosted 32 silent dinner parties in 11 cities across eight countries, including Germany, Australia andthe United States. "The way we communicate is changing so fast that we need to stop and think about it."

    According to a 2013 nation wide survey, restaurant noise came in second only to poor service among customer(顾客) complaints. And 19 percent of diners who took part in the survey said noise and crowds disturbed them most while eating out.

    Though silent dinners may seem curious, the idea is not a new one. Yogis(瑜伽信徒) have long enjoyed silent meals as part of a deepened practice. In fact, it was a trip to a temple(寺庙) in India by a man that encouraged one Brooklyn restaurant recently to add a silent dinner to its event programming.

    "We'll make a small speech at the beginning of the meal to make sure everyone understands what is happening and ask them not to speak or use their mobile phones for at least an hour," said EAT Green point owner Jordan Colon. And background music will be turned off, too.

    "It's funny; when I first opened EAT, I didn't play music for some time and people had very different reactions(反映) to that," said Colon. "Some people who come out to eat are ready to party, but it was so quiet without music. But I wanted to create an environment that makes you relaxed."

    Although personal reactions to a silent dinner may be various, in general they are more likely to get into a lot of talk afterwards, said Ryan. "At the end of the night people always have a lot to say about silence. But the most reaction is that there is always a good laugh."