题目

某行星半径为R，以其第一宇宙速度运行的卫星绕该行星的周期为T.如果在该行星上发射一颗同步卫星，并在其同步轨道上以速度v做匀速圆周运动时，可以与该行星自转同步.则同步卫星的轨道半径为__________，该行星的自转周期为___________. 答案：4π2R3／T2v2；8π3R3／T2v3从方框中选择适当的句子完成对话。Li Yang—L Bob—BL: Morning, Bob! Where are you going for your winter holiday?B: Morning, Li Yang! 1.L: I’m going there with my sister, too.B: That’s wonderful! 2.L: Thank you! Can you tell me any customs in England ? B: OK. 3. First, People in England drive on the left-hand side of the road.L: What’s the next one?B: Second, English people can’t ride their bicycles on the pavement.L: 4.B: Third, you can’t ask personal questions. For example, “How old are you?” “How much is your monthly salary (月薪)?” L: I see, thanks!B: You’re welcome. 5. L: OK! A. I tell you some important customs different from China.B. You can’t use your mobile phone in some trains.C. I’ll tell you more about it when you arrive in England.D. I’m going to return to my country—England.E. It’s very important to know about other countries’ customs. F. I can show you around.G. Anything else?A. I tell you some important customs different from China.B. You can’t use your mobile phone in some trains.C. I’ll tell you more about it when you arrive in England.D. I’m going to return to my country—England.E. It’s very important to know about other countries’ customs. F. I can show you around.G. Anything else?