Aerodynamics is a term that describes how force affects objects that move through air. Aerodynamics involves lift, weight, thrust and drag. The shape of an object and its weight affect its lift, and objects have an easier time moving through air than through water because water causes more drag than air.
Aerodynamics affect everything that moves. Each of the four forces involved in aerodynamics has an opposing force, and the ratio of opposing forces determines how an object moves. Airplanes must overcome weight, which is a force that, like gravity, pulls objects down to Earth. Lift is the opposite force that allows objects to fly. Different types of airplanes have different wing designs, depending on the intended use of the airplane. Round, narrow surfaces have less drag than flat, wide surfaces because more surface area is exposed and hit by air.
Because gravity keeps objects pulled down to Earth, airplanes are designed to be able to lift and fly safely, overcome drag and create thrust to move forward. The airplane's engine must create enough thrust to overcome drag. However, just as aerodynamics are important for getting objects to fly, aerodynamics are also important for getting objects to land safely. An object's aerodynamics affect its speed, its stopping power, and the smoothness of its movement through water or air.