The radius of the orbit, the energy of the system and the velocity of the electron, I am just going to present you the solutions.

是轨道的半径，系统的能量,以及电子的速度，我接下来会给你们讲解其方程的解法。

麻省理工公开课 - 固态化学导论课程节选

Suppose you're the driver of a trolley car, and your trolley car is hurtling down the track at 60 miles an hour.

假设你是一名电车司机，你的电车以60英里/小时的速度,在轨道上飞驰。

耶鲁公开课 - 公正课程节选

n So the velocity is given by this product of the quantum number n Planck constant 2 pi mass of the electron time the radius of the orbit, which itself is a function of n.

速度是量子数,普朗克常数2π乘以轨道半径的值,它自身也是n的函数。

麻省理工公开课 - 固态化学导论课程节选