So principle four is to reduce rotational inertia.

因此，第四条原则是减少惯量。

And since the force is the same on all of these, the ones that have the greatest I or rotational inertia are going to have the slowest acceleration.

由于作用在所有这些物上力相同，具有最大惯量物会有最慢加。

They have larger differences between their moments of inertia in different axes or what bowlers call RG differential, which makes the ball precess.

它们在不同轴上惯量之间存在较大差异， 或者投球手称之为 RG 差异，这使球产生进。

Examples of scalars are time, distance, mass, speed, volume, density, work, energy,   rotational inertia, and that's all I can think of.

标量例子有时间、距离、质量、、积、密、功、能量、惯量，这些就是我能想到。

Minimum moment of inertia, maximum moment of inertia and intermediate moment of inertia.

最小惯量、最大惯量和中间惯量。

We now have a torque and that torque is equal to the rotational inertia, instead of mass, times the angular acceleration, instead of the acceleration.

我们现在有一个力矩，这个力矩等于惯量乘以角加，而不是质量乘以加。

About half the designs relied on preconceived notions and use CD wheels, which are a real bad choice here because you're not looking for distance.

约有一半设计依赖于先入为主观念， 采用了CD轮，这在当前情况下是个极差选择， 因为你追求不是距离。 CD轮具有更大惯量和较差抓地力。

… the moment of inertia relates to mass, too, but it depends on how that mass is distributed.

...惯量也与质量有关， 但这取决于质量分布。

This means it has a higher rotational inertia.

这意味着它惯量更大。

So smaller radius of gyration just means lower moment of inertia, which translates into more rotation that a bowler can get on the ball.

因此， 较小回半径仅意味着较低惯量，这意味着投球手可以使球旋更多。

The farther away the mass is from the axis of rotation, the higher the object's moment of inertia.

质量离旋轴越远， 物惯量值越高。

It's the equivalent of a 16 foot lever arm or a back wheel four and a half feet in diameter, but without the downside of the extra weight or wasted rotational inertia, this thing barely crawls along.

这相当于一根16英尺长杠杆臂或一个直径四英尺半后轮，但却没有额外重量或浪费惯量所带来弊端，这东西几乎是在缓慢爬行。

So the maximum moment of inertia is rotating about any axis that passes through the equator of the ball.

因此， 最大惯量是绕任何通过球赤道轴旋。

Well then it has a lower moment of inertia.

那么它惯量就较小。

They have more rotational inertia and poor traction.

它们具有更大惯量和较差抓地力。

If you were to concentrate the entire mass of the ball onto a hoop with the same moment of inertia, it's radius would be the radius of gyration.

如果将整个球质量集中到具有相同惯量环上，则其半径就是回半径。