The sledge gained momentum as it ran down the hill.

雪橇从山上下冲时的力越来越大。

Angular momentum can accompany nonrotational motion.

非旋转的运可能伴随着有角。

The movement was gaining momentum.

这运势头越来越大。

Those variables for which it holds (e.g., momentum and position, or energy and time) are canonically conjugate variables in classical physics.

那些具有的变(如与位置,或能与时间)是经典力学里的正则共轭变。

According to this hypothesis, the solar wind could transfer energy and momentum to the plasma surrounding the earth only by wave motions along the magnetopause.

根据这项假说，太阳风只能靠磁层顶上的波，来能与给地球四周的电浆。