这就是著名的靠，摩擦力平衡的例子，现在我想讨论一个，可以在重力作用下，自由摆动的悬挂物体。

So you saw in a striking example of where friction helped us to balance, and now I want to discuss an object that is hanging and that can freely swing due to gravity.

youdao

然而，钢架的柱子是可以随着摇晃自由上下摆动，有钢管托牢牢固定在基座上。

The frame’s columns however are free to rock up and down within steel shoes secured at the base.

youdao

然而，钢架的柱子是可以随着摇晃自由上下摆动，有钢管托牢牢固定在基座上。

The frame's columns, however, are free to rock up and down within steel shoes secured at the base.

youdao