We are interested in determining the amount of linear momentum delivered to the electron by the field.

我们对确定场传递给电子的线性动量的大小感兴趣。

In motions of rotation angular momentum appears in much the same way as linear momentum appears in motion of translation.

在旋转运动中的角动量产生的方式与平移运动中的线动量的产生是基本相似的。

In other words, the vertical component of its linear momentum remains zero, since there is no resultant vertical force.

换句话说，因为没有竖直方向的合力，所以线动量的竖直方向仍为零。

Angular momentum: the vector product of the position vector (from a reference point) and the linear momentum of a particle.

角动量：(有参照点)的矢量和粒子线性动量的向量积。

Just as linear momentum is the product of mass and velocity, so the angular momentum of a body is defined as the product of its moment of inertia and its angular velocity.

正如线性动量是质量和速度乘积一样，物体角动量也定义为其惯性矩和角速度的乘积。