dragging

Dragging is the act of pulling an object along a surface or through a medium. In everyday use, it describes moving items by applying a force that overcomes friction. In physics, drag is the resistive force exerted by a fluid on a body moving through it, acting opposite to the direction of motion.

In fluids, drag consists of form drag (pressure differences around the body) and skin-friction drag (viscous shear on the surface). The total drag rises with fluid density, velocity squared, and cross-sectional area, while shape and flow regime (Reynolds number) determine the distribution between components.

Drag is commonly described by the equation F_d = 0.5 ρ v^2 C_d A, where ρ is fluid density, v is relative velocity, A is cross-sectional area, and C_d is the drag coefficient. For very small objects at low Reynolds numbers, Stokes’ law applies: F_d = 6π μ R v.

Applications include the design of vehicles, aircraft, and sporting equipment, where reducing drag improves efficiency and performance. Drag-reduction strategies include streamlining, surface finishing, and flow-control techniques. Drag measurements and simulations validate models in fluid dynamics.

In computing, dragging refers to moving on-screen objects by clicking or touching and holding, then dragging them to a new location. This interaction, known as drag-and-drop, is common in graphical user interfaces and touch interfaces.

Manual dragging of heavy or awkward objects presents safety risks; proper lifting techniques or mechanical aids are recommended to reduce injury risk.