When she draws her arms inwards, that distribution is reduced, so her speed must pick up to counteract this difference and keep her total momentum constant.
当收起双臂时，分布空间减少，于是其速度一定会加快以弥补差异，从而保持总动量不变。
2
The amount of angular momentum, say, a spinning skater has depends on both the speed of rotation, and the weight and distribution of mass around the center.
角动量的大小，取决于旋转中的滑冰选手的旋转速度、体重和绕旋转中心的质量分布。
3
Based on the limited momentum propagation velocity, this paper presents the solution of the transient momentum equation by Laplace transform. The distribution functions of velocity and eddy are given.