大家都知條式係
F=Gm底1m底2/r^2
G=6.67x10^(-11)
但係我5明r點解要乘10^3
e.g. 地球同月球之間既引力
地球重5.97 x 10^24 kg
月球重7.35 x 10^22 kg
距離(r)=3.84 x10^5 km
6.67x10^(-11) x 5.97 x 10^24 x 7.35 x 10^22
---------------------------------------------------------------
(3.84 x10^5 x "10^3" )^2
gravitational force
2010-07-12 2:16 am
回答 (2)
2010-07-12 2:30 am
✔ 最佳答案
因為在 F 的公式中:F = Gm1m2/r2
r 的單位為 metre (m), 距離及長度的 SI unit 皆為 m.
所以, 將 km 轉做 m 時, 必需乘上 103, 因為 1 km = 103 m,
參考: Myself
2010-07-18 9:04 am
Not only the equation for graviational force, but in ALL physics equations, you have to use "kg" for unit of mass, "m" (metre) for unit of length, and "s"(second) for unit of time. These are the fundamental units in physics.
Since the given distance r is in "km"(kilometre), which is NOT the fundamental unit for distance (or length), you thus have to change the unit from "km" to the fumdamrntal unit "m"(metre), using the conversion 1 km = 1000 m.
Since the given distance r is in "km"(kilometre), which is NOT the fundamental unit for distance (or length), you thus have to change the unit from "km" to the fumdamrntal unit "m"(metre), using the conversion 1 km = 1000 m.
收錄日期: 2021-04-29 17:36:03
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100711000051KK01184