题干

如图,斜面上有a、b、c、d四个点,ab=bc=cd,从a点以初速度v0水平抛出一个小球,它落在斜面上的b点,速度方向与斜面之间的夹角为θ;若小球从a点以初速度 2 v0水平抛出,不计空气阻力,则小球(  )

A:将落在bc之间

B:将落在c点

C:落在斜面的速度方向与斜面的夹角大于θ

D:落在斜面的速度方向与斜面的夹角等于θ

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答案(点此获取答案解析)

B,D

同类题2

完形填空

     When people think of tigers, they think: strong and dangerous. But now, the big animal is calling for our help.

     There were once eight kinds of   1   in the world, but three died out during the 20th century. In the last 70 years, the   2   of Siberian tigers (东北虎) has gone from as many as 300 to   3   22 somewhere. The Siberian tiger has been   4   dying out completely. If the government doesn't make any efforts, it's quite   5   that there will be no more Siberian tigers in China in ten to twenty years.

     In order to double the number of wild tigers in the   6   ten years, the World Wildlife Fund for Nature has started a program recently. It   7   save wild tigers and put an end to tiger hunting and killing. China, together with twelve other   8  , has joined in.

     Wild animals, such as red deer and wild pigs, are the main   9   of the tigers. The hunting of these animals is the greatest threat(威胁) to tigers. So the most important thing is   10   the animals that tigers eat. To protect the wild tigers, we need to call on more people to stop eating and hunting wild animals.

 1 A. pigs        B. tigers             C. deer              D. lions

 2 A. name       B. kind              C. number           D. type

 3 A. less than    B. more than        C. bigger than       D. larger than

 4A. in need of   B. in danger of      C. in front of  D. in spite of

 5 A. possible     B. impossible   C. necessary         D. unnecessary

 6 A. last        B. next             C. past             D. first

 7 A. aims to     B. used to           C. refuses to         D. aimed to

 8 A. cities        B. provinces          C. countries          D. places

 9 A. friends      B. food               C. members          D. relatives

 10 A. to sell     B. to kill           C. to save           D. to buy