The sack is too heavy to lift—you'll have to drag it.

这麻袋太重了，提不起来。你得拖着走。

The aerofoil of a wing creates more lift than drag, but exactly how much depends on its design and the speed of the air passing over it.

飞机上的机翼制造升力超过阻力，但具体取决于机翼的设计和当时经过的空气流动速率。

But it was a birdlike tail that really amped up the aerodynamics, dampening the drag from the body and wings, as well as boosting the lift that lags under vehicle weight and cargo load.

的确鸟儿尾巴一样的飞机尾部改善了空气动力学性能，缓解了机体和机翼的阻力，同时还大大的增加了向上的力，缓释了由于飞机本身和货物重量而产生的向下的力。

In aerodynamic terms, lift is a function of weight, thrust and drag (air resistance).

在空气动力学上，升力是重量，推力和阻力(空气阻力)的相关的函数。

At altitude, the air pressure is lower, and so are aerodynamic effects such as drag and lift, ultimately causing balls to travel faster and straighter than they would at lower altitude.

由于地处高海拔地区，气压较低，因而作用在球上的阻力及升力所产生的空气动力效应也会发生相应反应，最终导致球在空中飞行速度比在低海拔地区快，飞行的路线也更直。