题干

如图所示,从水平地面上的A点,以速度v1在竖直平面内抛出一小球,v1与地面成θ角.小球恰好以v2的速度水平打在墙上的B点,不计空气阻力,则下面说法中正确的是(   )

A:在A点,仅改变θ角的大小,小球仍可能水平打在墙上的B点

B:在A点,仅改变速度v1大小,它仍可能水平打在墙上的B点

C:在B点以大小为v1的速度水平向左抛出小球,则它可能落在地面上的A点

D:在B点水平向左抛出小球,让它落回地面上的A点,则抛出的速度大小一定等于v2

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答案(点此获取答案解析)

D

同类题5

阅读下面图表,从每小题所给的A、B、C、D四个选项中选出一个最佳选项。

    There will be three kids movies in theaters. Let's know the main idea of them first.

The Snow Queen

    The Snow Queen tells the story of the Snow Queen who covered the world in ice, setting out to destroy (破坏) everything, including the family of the glassmaker Vegard. Luckily, Vegard and his wife were able to save their daughter Gerda and their son Kai before it was too late. But when Kai was discovered by the Snow Queen's servant (仆人), Gerda took a journey across the icy wonderland, facing difficulties and finding new friends to set Kai free, to beat the Snow Queen and warm the hearts of people everywhere.

Angels Sing

    As a child, Michael Walker wished every day could be Christmas. That continued, until a tragic accident broke down his holiday spirit. Thirty years later, Michael still can't feel any joy for Christmas, though encouragement comes from his playful wife (Connie Britton) and kind parents (Kris Kristofferson and Fionnula Flanagan). But when his young son (Chandler Canterbury) face a tragedy (悲剧), Michael needs to make amends (赔偿) with his past. A mysterious man named Nick (Millie Nelson) gives Michael a gift that can give him the courage to find the Christmas joy that he lost.

Adventures of the Penguin King

    Rex, a young King Penguin, has been away from his home for three years, learning to hunt in the wild oceans, but now he's back in Penguin City. His task: to find a wife, settle down and raise a chick. But can he survive in the bad conditions on an island at the bottom of the world?