问题
不定项选择
如图所示,一只光滑的碗水平放置,其内放一质量为m的小球,开始时小球相对于碗静止于碗底,则下列哪些情况能使碗对小球的支持力大于小球的重力

A.碗竖直向上做加速运动
B.碗竖直向下做减速运动
C.碗竖直向下做加速运动
D.当碗由水平匀速运动而突然静止时
答案
ABD
如图所示,一只光滑的碗水平放置,其内放一质量为m的小球,开始时小球相对于碗静止于碗底,则下列哪些情况能使碗对小球的支持力大于小球的重力
A.碗竖直向上做加速运动
B.碗竖直向下做减速运动
C.碗竖直向下做加速运动
D.当碗由水平匀速运动而突然静止时
ABD
根据对话内容,从方框内选出能填入空白处的最佳选项,其中有两项为多余项。 | |
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A: Hi, Max. I’m glad to see you here. B: Hello, Jane! 1 A: Look! I’m wearing a new coat made of animal fur. 2 B: It’s hard to say. A: 3 B: Yes. But do you know how many animals were killed for your coat? A: 4 B: Some people kill animals, and then they get money by selling the meat and fur. A: That’s terrible. 5 B: Good. Animals are our friends. We should share the world with them together. 1.__________ 2. __________ 3. __________ 4. __________ 5. __________ |