krafttidsintegral

Krafttidsintegral is a term used in physics to denote the integral of force with respect to time over a given interval. In many contexts it is equivalent to what is commonly known as impulse. Formally, for a force function F(t) defined on an interval [t0, t1], the krafttidsintegral is J = ∫_{t0}^{t1} F(t) dt. In vector form it is J = ∫ F(t) dt, yielding a vector impulse whose direction matches the force.

Its physical meaning is the change in momentum that the force imparts to a body, according to the impulse-momentum theorem: Δp = J. For a particle with constant mass, Δp = m Δv, so the krafttidsintegral equates to the momentum change.

Units are newton-seconds (N·s). If the force is constant, J = F Δt. The term is commonly used in dynamics, impact analysis, and engineering applications involving short-duration forces, such as collisions, shocks, or actuator impulses. It is distinct from work, which is the time integral of power or the integral of force with respect to displacement, ∫ F · dr.

Computationally, the krafttidsintegral is evaluated analytically when F(t) is known in closed form, or numerically for measured data using methods such as the trapezoidal rule or Simpson's rule.

See also: impulse, momentum, Newton's laws, impulse-momentum theorem.