Impulsion

Impulsion, in physics, refers to the impulse delivered by a force acting over a period of time. It is defined as J = ∫ F dt, and for a single particle it equals the change in momentum, J = Δp = p_f − p_i. If the force is constant, J = F Δt. The conventional unit is the newton-second (N·s).

Impulse is governed by the impulse–momentum theorem, which states that the impulse on an object equals the resulting change in its momentum. This concept explains why short, high-magnitude forces can produce large velocity changes, and it applies to collisions, propulsion, and any situation involving force over time.

In signal processing and systems theory, an impulse (often modeled by the Dirac delta function) is an idealized, instantaneous input used to characterize a system's response, known as the impulse response.

In biology and neuroscience, a nerve impulse (action potential) is a temporary, propagating change in membrane potential that transmits information along a neuron; while not identical to mechanical impulse, the term is closely related in everyday language.

Usage: In French, impulsion means impulse or drive and appears in scientific and figurative contexts; in English, impulsion is used chiefly in technical settings to denote impulse, while "impulse" and "driving force" are common in general language.