滑雪者在下坡时获得了动力，速度越来越快。

The skier gained ___momentum going downhill and sped up.

新产品发布后，公司的发展势头越来越强劲。

After the new product launch, the company gained strong ___momentum for growth.

物理课上，老师解释了如何计算滚下山坡的球的动量。

In physics class, the teacher explained how to calculate the ___momentum of a ball rolling down the hill.