Theorie Basiskurs

Gravity and its impact are known by everyone and are the easiest to understand. Gravity attracts all objects to the ground. When you hold an object in your hand and drop it, you see the effect of gravity right in front of you.

^{Image: Frits Ahlefeldt CC BY-NC-ND 2.0, Link}

Without gravity, the objects would float around. This can be seen, for example, when taking pictures from the ISS space station.

To lift an object from the ground, a force is required. The magnitude of this force depends on the mass of the object. For example, lifting a full water tank requires more force than lifting an empty water tank.

The force that causes an airplane to raise from the ground is called lift. We'll discuss how it's generated later. But first we have to take a closer look at propulsion.