[題目] 圓周運動
[領域] 圓周運動 角速度 (題目相關領域)
[來源] 學校老師給的作業 (課本習題、考古題、參考書...)
[題目]
Under some circumstances, a star can collapse into an extremely dense object
made mostly of neutrons and called a neutron star(star碰撞變成neutron star). The density of a neutron
star is roughly 10^14 times(密度為10^14倍) as great as that of ordinary solid matter. Suppose we
represent the star as a uniform, solid, rigid sphere, both before and after
the collapse. The star's initial radius was 7*10^5 km(一開始的半徑) (comparable to our sun); its
final radius is 16 km(最後的半徑).
Question:If the original star rotated once in 30 days, find the angular speed of the
neutron star.
[瓶頸] (寫寫自己的想法，方便大家為你解答)
以上是原本的題目 中文是我自己加上去
首先我先把星星的速度換成rad/s, 然後再用I_1w_1=I_2w_2
I=mr^2 所以就變成mr_1^2 w_1 = mr_2^2w_2 m消掉
所以這樣可以解出w_2
可是我不太懂為什麼他要給我們星星的密度 會用到嗎??
還是質量會跟著密度改變???可是這樣解的出來嗎
還是可以直接忽略他給的密度 算出來的w_2就是答案?
希望了解的人可以幫我解答一下 謝謝
有其他看法也歡迎一起討論!! 謝謝
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