来自《耶鲁大学开放课程：基础物理 第17集 第17集》
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Either there is something moving linearly要么是有某个量 -
with a coordinate that you can call x,关于 x 坐标做线性运动 -
or it's rotating or twisting by an angle you can call θ.要么是关于某个 θ 做转动或者扭动 -
And if you want to find out the frequency of vibration,如果想要找出振动的频率 -
you have to disturb it from equilibrium,就需要关于平衡位置做扰动 -
either by pulling the mass or by twisting the cable要么拉一下物体 要么扭一下绳索 -
or displacing this pendulum或者晃动单摆 -
from its ideal position here,让它偏离平衡位置 -
then finding the restoring torque. Yep?然后找出回复力矩 请讲 -
That's a very good point.这是个好问题 -
His question is,他的问题是 -
if I gave you a cable如果给你一个绳索