问题
选择题
举世瞩目的“神舟”六号航天飞船的成功发射和顺利返回，显示了我国航天事业取得的巨大成就。已知地球的质量为M，引力常量为G，设飞船绕地球做匀速圆周运动的轨道半径为r，则飞船在圆轨道上运行的速率为[ ]
A．
B．
C．
D．
答案
答案：A
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举世瞩目的“神舟”六号航天飞船的成功发射和顺利返回，显示了我国航天事业取得的巨大成就。已知地球的质量为M，引力常量为G，设飞船绕地球做匀速圆周运动的轨道半径为r，则飞船在圆轨道上运行的速率为[ ]
A．
B．
C．
D．
答案：A
| 从方框中选词填空。 | |
2. Justin has a computer game. He likes to ______ computer games. 3.—______ play basketball.—That ______ interesting. 4. I have a baseball ______. I like to play baseball. 5. My grandmother ______ a TV in her room. She ______ TV every day. 6. My friend has a great sports ______. He has all kinds balls in his room. |