In the vacuum environment, feather and iron ball fall to the ground simultaneously from the same height.

在真空环境中，羽毛和铁球从同一高度同时落到地面。

This is roughly analogous to the effect that a massive object such as the Sun(the iron ball) has on spacetime (the material): it stretches and curves and warps it.

这大致类似于太阳这样的庞然大物（铁球）对于时空（底垫）的作用：铁球使底垫伸展、弯曲、翘起。

Now, there's lots of ways to do this, but the one most similar to an invisibility cloak is a radar-absorbent material that coats the plane, like iron ball paint.

现在，有很多方法可以做到这一点，但与隐形斗篷最相似的是一种覆盖在飞机上的雷达吸收材料，如铁球涂料。

At the line where its base descended to the parapet there were half a dozen iron balls, precisely like cannon-shot, standing loosely in a groove, and on these the dome rested its whole weight.

在它的底部下降到护墙的那条线上，有六个铁球，就像大炮一样，松散地立在一个凹槽里，圆顶的全部重量都靠在这些铁球上。

BRUCE LEE: Well, a karate punch is like an iron bar -- whack! A Gung Fu punch is like an iron chain with an iron ball attached to the end and it goes Wang! And it hurts inside.

空手道击打就像一块铁条，打出去是whack的一声；功夫击打则像拴着铁球的铁链，Wang的一声就伤到对手体内了。