kraftmoment

Kraftmoment, in English often called torque or moment of a force, is a measure of the rotational effect produced by a force applied at a distance from a pivot or rotation axis. It depends on the magnitude of the force, the distance from the pivot (the lever arm), and the angle between the force and the lever arm. The standard vector form is τ = r × F, where r is the position vector from the pivot to the point of application and F is the force. The magnitude is τ = r F sin(θ), with θ as the angle between r and F.

The torque has a direction that is given by the right-hand rule, corresponding to the axis around which the rotation occurs. In many engineering and physics contexts, the sign of the torque indicates the sense of rotation (for example, positive for counterclockwise when viewed from a chosen direction).

Units and relation to other quantities: the unit of Kraftmoment is the newton-meter (N·m). Although the same unit is used for energy (also joules), torque represents rotational effect and not work or energy; the two have different physical meanings.

Applications and laws: Kraftmoments are central to analyzing rotational motion. The total torque about a point equals the rate of change of angular momentum. In rotational dynamics, the relation is τ_total = I α, where I is the moment of inertia and α is the angular acceleration. In statics, equilibrium requires that the sum of all torques about any point is zero.

Terminology: Kraftmoment is the German term for torque. It is closely related to Drehmoment; both describe the moment of a force, though Drehmoment is the more common term in many modern German texts. Common examples include opening a door, turning a bolt with a wrench, or applying a force to a lever.