which is kW,

也就是 kW
little k then W is thousand watts.

k 接上 W 就是一千瓦特
So, if you've got a 60-watt bulb,

所以如果你有一个六十瓦的灯泡
it's consuming energy at the rate of 60 joules per second.

表示它每秒消耗六十焦耳的能量
That's the meaning of a 60-watt bulb.

这就是六十瓦灯泡的意思
Okay, now I'm going to do the next generalization,

我接下来要把这些内容再推广一下
which is when the force is not a constant but varies with x.

就是当力随着 x 改变而不是恒定值的情况
So, do we know any example of a force that varies with location?

我们知道什么力随位置改变的例子呢
A spring is one example.

弹簧是一个例子
Even gravity I think we know is not a secret,

甚至重力我想大家都知道
the force of gravity is m · g near the Earth,

地球表面的重力是 m · g
but if you go sufficiently far

但如果你离地面足够远