So principle four is to reduce rotational inertia.

因此，第四条原则是动惯量。

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.

由于作用在所有些物体上的相同，具有最大动惯量的物体会有最慢的加速度。

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

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

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

标量的例子有时间、距离、质量、速度、体积、密度、功、能量、动惯量，些就是我能想到的。

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

最小动惯量、最大动惯量和中间动惯量。

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，个等于动惯量乘以角加速度，而不是质量乘以加速度。

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.

约有一半的设计依赖于先入为主的观念， 采用了CD轮，在当前情况下是个极差的选择， 因为你追求的不是距离。 CD轮具有更大的动惯量和较差的抓地。

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

...动惯量也与质量有关， 但取决于质量分布。

This means it has a higher rotational inertia.

意味着它的动惯量更大。

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， 较小的回半径仅意味着较低的动惯量，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， 物体的动惯量值越高。

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.

相当于一根16英尺长的杠杆臂或一个直径四英尺半的后轮，但却没有额外重量或浪费的动惯量所带来的弊端，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， 最大动惯量是绕任何通过球赤道的轴旋。

Well then it has a lower moment of inertia.

那么它的动惯量就较小。

They have more rotational inertia and poor traction.

它们具有更大的动惯量和较差的抓地。

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.

如果将整个球的质量集中到具有相同动惯量的环上，则其半径就是回半径。