问题
选择题
如图所示实线和虚线分别是同一个单摆在A、B两个大小相同的星球表面的振动图象,其中实线是A星球上的,虚线是B星球上的,则两星球的平均密度∶
是( )
A.1∶2 B.∶1 C.8∶1 D.4∶1
答案
答案:D
单摆周期,可得:
,
星球平均密度,平均密度之比:
如图所示实线和虚线分别是同一个单摆在A、B两个大小相同的星球表面的振动图象,其中实线是A星球上的,虚线是B星球上的,则两星球的平均密度∶
是( )
A.1∶2 B.∶1 C.8∶1 D.4∶1
答案:D
单摆周期,可得:
,
星球平均密度,平均密度之比:
用方框中所给单词或短语的适当形式填空。 | |
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1. If you want to have the ________hair of all, you should use the kind of shampoo. 2. In Disney cartoons, "________and Beast" is very popular with Chinese children. 3. Many ads are confusing and_______,so many people bought some that they didn't need at all. 4. More new_______make our life more convenient and colorful. 5. If you use this soap, you will have_______skin. |