Now, when you look at this there is something quite remarkable and the remarkable thing x - throughout this whole trajectory-- if there is no air draft, - if there is no friction-- is not changing.

你们可以看到,有件事非常值得注意,可以注意到,方向的速度，is，that，the，velocity，in，the，x，direction,在整个轨迹当中-,如果没有空气阻力，也没有摩擦力-,是不会改变的。

youdao

In like manner, meteors super heat the air along their trajectory, and UFOs not only create their own gravity centers, they also create their own magnetic fields.

以类似的方式，流星使沿路的空气变得过热，而U FO不仅会生成自己的重力中心，还会产生它们自己的磁场。

youdao

The effects of frication, air frication on the speed and trajectory of projectiles have been fully considered.

主要考虑了摩擦力、空气阻力等因素对弹丸的速度和轨迹的影响。

youdao

Unlike most shots, in which the golfer largely controls the flight of the ball through the air, a putt's terrestrial trajectory can be altered by a lot more variables the speed of the green, the contours of the earth, a spike mark, or any little object that might be in the ball's path.

WSJ: Tiger Woods Should Credit His Return to No. 1 on Improved Putt