projektilen

Projektilen, or the projectile, is any body launched into the air that, after leaving its launcher or hand, is influenced by gravity and, in most cases, air resistance. The term is used across physics, ballistics, and sports to describe objects whose subsequent motion is not actively propelled.

In the idealized model of projectile motion, air resistance is neglected. The horizontal velocity remains constant while the vertical velocity changes under the constant acceleration of gravity. The resulting path is a parabola. Key quantities describe the flight: time of flight, maximum height and range. If the launch height equals the landing height, the time of flight is T = 2 v0 sin(θ) / g, the range is R = v0^2 sin(2θ) / g, and the maximum height is H = v0^2 sin^2(θ) / (2g), where v0 is the initial speed, θ is the launch angle, and g is the acceleration due to gravity.

Real-world projektilen experiences air resistance, which reduces speed and bends the trajectory downward. Drag depends on the air density, the projectiles’ cross-sectional area, shape, and velocity, often described by the drag coefficient Cd. Drag alters time of flight, range and height, with heavier or denser projectiles generally retaining velocity longer.

Projektilen encompasses a wide range of objects, including bullets, artillery shells, arrows, javelins and other sports projectiles. In contrast to guided missiles or rockets, a projektil is propelled only at launch and follows a ballistic trajectory thereafter. The study of projektilen blends mechanics, material science and aerodynamics, informing weapon design, sports science and safety analyses. In Scandinavian languages, projektilen denotes “the projectile.”