设地球是半径为R的均匀球体,质量为M,设质量为m的物体放在地球中心,则物体受到地

题型:选择题

问题:

设地球是半径为R的均匀球体,质量为M,设质量为m的物体放在地球中心,则物体受到地球的万有引力为(  )

A.零

B.

GMm
R2

C.无穷大

D.无法确定

考点:万有引力定律的其他应用
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I met Kumkum at a children’s home in Delhi. It is a home  小题1:  children who are sick are provided treatment and care before  小题2:(send) to some other orphanage. Kumkum was 7 years old, and a very brave soul. Despite suffering from tuberculosis(肺结核), I never saw  小题3: crying. She had lost her parents and was struggling herself through this terrible disease.

Upon meeting, we took an instant liking  小题4: each other. Every Saturday I would visit Kumkum and play with her. She would love to sit on my lap. It was one such moment that the child felt like  小题5: (kiss) me... and I suddenly remembered that she was suffering from tuberculosis which is a communicable(传染性的)disease. I tried to stop her   小题6: she really wanted to show her affection for me, so I overcame my fear and let her place the   小题7:  gentle and sweet kiss on my cheek that I ever had.

Although I overcame my fear at that moment, I   小题8: (not forgive) myself ever since for refusing her  小题9:  (initial). Although the child kissed me, I think she sensed my hesitation  小题10: she has never kissed me again. I will never forget that the most beautiful thing in this world is a child’s kiss... so full of love and innocence.

题型:选择题

下列说法正确的是

A.煤的气化是物理变化

B.蛋白质、橡胶和塑料都是天然高分子

C.乙烯与HCl加成后可得到聚氯乙烯的单体

D.乙醇可以被氧化为乙酸,二者都能发生取代反应

题型:选择题

除国家税务总局另有规定外,纳税人一经认定为一般纳税人后,()转为小规模纳税人。

A.不得

B.可以

C.随时可以

D.经过一段时间可以

题型:选择题

热咀附近不可以设置独立回路的冷却水,以防降低热咀的温度。

题型:选择题

以下哪项不属于信息安全管理的工作内容()

A.信息安全培训

B.信息安全考核

C.信息安全规划

D.安全漏洞扫描

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