在地球的圆轨道上运动的人造卫星,它到地球表面的距离等于地球半径R,设在地球表面的

题型:问答题

问题:

在地球的圆轨道上运动的人造卫星,它到地球表面的距离等于地球半径R,设在地球表面的重力加速度为g,求:

(1)地球的第一宇宙速度 

(2)该卫星运动的周期.

考点:万有引力定律的其他应用宇宙速度
题型:问答题

锅炉排污量增大,以下哪几个量将发生变化:()

A、锅炉液位

B、炉水碱度

C、出口蒸汽量

D、锅炉给水量E锅炉加药量

题型:问答题

One day while a girl was walking in the woods she found two starving songbirds. She took them home and put them in a small (16) She cared for them and felt great love for them.

Once the (17) and per of the two birds flew from the cage. Therefore, (18) he flew close, she grasped him (19) She felt glad, but suddenly she felt the bird go limp. She opened her hand and (20) in horror at the dead bird.

She noticed the other bird moving back and forth on the edge of the cage. She could feel his great need for (21) She lifted him from the cage and (22) him softly into the air. The bird circled once, twice, three times.

The girl watched delightedly at the bird’ s enjoyment. Her heart was no longer (23) with her loss. Suddenly the bird flew closer and (24) softly on her shoulder. It sang the sweetest melody that she had ever heard.

The fastest way to (25) love is to hold on it too tightly, while the best way to keep love is to give it WINGS!

24().

A.landed 

B.sat 

C.slept 

D.stood

题型:问答题

行社采用的会计政策,在每一会计期间和前后各期应保持一致,不得随意变更。但是,满足下列条件之一的,可以变更会计政策,即对相同的交易或事项由原来采用的会计政策改用另一个会计政策。()

A、法律、行政法规要求变更

B、国家统一的会计制度要求更更

C、会计政策变更能够提供更可靠、更相关的会计信息

D、会计政策变更能够提升行社的经营成果

题型:问答题

()证明了奇点是广义相对论的必然推论。  

A、爱因斯坦

B、史瓦西

C、拉普拉斯

D、彭罗斯和霍金

题型:问答题

急性智齿冠周炎治疗原则中不包括

A.消炎
B.镇痛
C.切开引流
D.增强抵抗力
E.拔除患牙

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