题目内容
在某个半径为
的行星表面,对于一个质量
kg的砝码,用弹簧称量,其重力的大小
。则:
①请您计算该星球的第一宇宙速度
是多大?
②请计算该星球的平均密度。(球体积公式
,
,结果保留两位有效数字)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140212914519.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140212976386.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213023543.png)
①请您计算该星球的第一宇宙速度
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213070302.png)
②请计算该星球的平均密度。(球体积公式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213148706.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241402132261100.png)
(1)
m/s(2)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213382927.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213319478.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213382927.png)
(1)
m/s2 ………………2分
……………1分 解得:
………………1分
代入数值得第一宇宙速度:
m/s……………………1分
(2)由
得
……………2分
又![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213148706.png)
……………………2分
代入数据解得
……………………1分
本题考查万有引力提供向心力的应用,注意黄金代换的应用,在星球表面根据重力等于万有引力,半径为星球半径可求出密度表达式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213475698.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213553786.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213631531.png)
代入数值得第一宇宙速度:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213319478.png)
(2)由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213772884.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213819748.png)
又
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213148706.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241402139281089.png)
代入数据解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140213382927.png)
本题考查万有引力提供向心力的应用,注意黄金代换的应用,在星球表面根据重力等于万有引力,半径为星球半径可求出密度表达式
![](http://thumb2018.1010pic.com/images/loading.gif)
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