它移动着，力会，垂直于绳子和r的平面，你们可自己知道为什么。

And as it moves, the torque will always be perpendicular to the plane through the string and r.You can just see that for yourself why that is.

youdao

它移动着，力会，垂直于绳子和r的平面，你们可自己知道为什么。

And as it moves, the torque will always be perpendicular to the plane through the string and r.You can just see that for yourself why that is.

youdao