而第二个例子中，用一辆车撞另一辆，后一辆质量是它的二倍-，不知道速度多大-，现在我们得到什么？

The second case, I bounce one car onto another one - which is twice the mass — - certain velocity which I don't know what it is — and now what are we going to get?

youdao

不为0，为0的是重量，This，is，weightless，，here，your，weight，is，double,这里是零重量，这里是二倍重量,这里是正常重量，这里是二倍重量,然后又是新的一轮,自由落体。

g here your weight is normal, here your weight roughly doubles and you go into another free-fall period and the cycle from here to here is about 90 seconds.

youdao

Cereal would be--a serving of cereal would be about the amount that would fit in a wine glass, but people think that you fill up a bowl and that becomes a serving, but a typical amount of cereal that people serve themselves might be two or three times what the ordinary size is.

这是一餐份量的麦片,放在酒杯里大概那么多,但人们认为满满一碗才是一份,人们通常所食用的麦片,是原来大小的二到三倍

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选