ATMOSPHERIC DRAG Meaning and
Definition
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Atmospheric drag, also known as aerodynamic drag or air resistance, refers to the force that opposes the motion of an object as it moves through the Earth's atmosphere. It is a significant factor that affects the velocity and trajectory of objects such as aircraft, spacecraft, missiles, and projectiles.
This drag force occurs due to the collision between the object's surface and the air particles present in the atmosphere. As an object moves through the air, it pushes aside the molecules in its path, creating an area of increased pressure called a bow shock. The air particles then fill in behind the object, resulting in an area of decreased pressure known as a wake. The pressure difference between these two regions causes a force to act against the object's motion, which is referred to as atmospheric drag.
The magnitude of the drag force depends on several factors, including the object's shape, velocity, and the density of the surrounding atmosphere. Generally, larger and more streamlined objects experience less drag than smaller and irregularly shaped ones. Likewise, higher velocities and denser atmospheres increase the drag force.
Atmospheric drag has numerous implications in various fields of engineering and physics. In aerospace, it is crucial for designing spacecraft trajectories, determining reentry dynamics, and calculating fuel consumption. In sports, drag is taken into account when designing aerodynamic equipment such as cycling helmets or swimsuits. Understanding atmospheric drag is also vital in fields like meteorology, climatology, and environmental science to model the movement and dispersion of pollutants or the behavior of air masses.
Etymology of ATMOSPHERIC DRAG
The word "atmospheric" comes from the Late Latin word "atmosphericus", which was derived from the Greek word "atmosphaira", meaning "vapor" or "vapor sphere". The word "drag" comes from the Old Norse word "drǫg", which means "pull", "draw", or "carry".
The term "atmospheric drag" is usually used to describe the resistance or force exerted by the Earth's atmosphere on a moving object, such as a spacecraft or an aircraft. The combination of these two words describes the phenomenon of air resistance or the force that opposes the motion of an object through the atmosphere.
