Modstandskraften

Modstandskraften is a term used in Danish and Norwegian to denote the resistance or opposing force acting on a body in motion. In physics, it refers to the force that opposes the applied or driving force and is accounted for in the analysis of motion using Newton’s laws.

The concept covers several types of opposing forces. Friction between contacting surfaces can be static (preventing motion) or kinetic (opposing ongoing motion). In fluids, the resisting force is commonly called drag or air resistance, which increases with speed. Viscous drag in liquids is another form of opposing force that depends on velocity and fluid properties. While drag can often be described by models that scale with velocity squared at higher speeds, low-speed regimes may show a more linear relationship.

In practice, modstandskraften influences performance, efficiency, and safety. In vehicles, it affects acceleration, fuel consumption, and braking requirements. In projectiles and aircraft, drag determines range, speed, and maneuverability. Engineers design shapes, surfaces, and control systems to minimize unwanted resistance or to manage it effectively under given operating conditions.

Conceptually, the net force on an object is the sum of all applied forces and resistive forces; when these balance, the object moves with constant velocity or remains at rest. The term is widely used in Scandinavian languages and is applied across physics, engineering, and related disciplines to describe any opposing force that reduces the effect of motion.