Fightfish said:Nope, 'air friction' or drag only exists if the object is moving relative to the medium, and thus this doesn't explain why things float (let's say an object is moving downwards, the drag force will only slow it down, but not cause it to move upwards).
They float due to upthrust ie net upwards force due to pressure differences acting on the different surfaces of the object. If the upthrust on the object is greater than or equal to the weight of the object, then it floats.
Air friction, also known as air resistance, is the force that opposes the movement of objects through the air. This is caused by the collision of air molecules with the surface of the object, creating a drag force that slows down its motion.
Whether an object floats or sinks is determined by its density compared to the density of the fluid it is immersed in. Objects with a higher density than the fluid will sink, while objects with a lower density will float. The shape and surface area of an object also play a role in its ability to float.
For airplanes to fly, they must generate enough lift to overcome the force of gravity. Air friction plays a crucial role in this process, as it creates drag that must be overcome by the engines and wings of the airplane. The shape and design of an airplane's wings are specifically designed to minimize air friction and maximize lift.
Air friction cannot be completely eliminated, but it can be reduced through various means such as streamlining the shape of objects, reducing their surface area, and using smooth and streamlined materials. For example, race cars and airplanes are designed to minimize air friction in order to achieve greater speeds.
The force of air friction increases as the speed of a falling object increases. This means that as an object falls, it experiences increasing air resistance, which ultimately limits its acceleration. This is why objects eventually reach a terminal velocity, where the air friction force is equal to the force of gravity, and they no longer accelerate.