Kokonaisimpulssi

Kokonaisimpulssi is a concept in physics describing the integral of the external force acting on a body over a time interval. It represents the total change in the body’s momentum during that interval. The impulse is defined by J = ∫ F dt, where F is the force vector and t is time. Because momentum p = m v, and for a body with constant mass the impulse equals the change in momentum, J = Δp = p2 − p1. If the force is constant during the interval Δt, then J = F Δt. The units are newton-seconds (N·s), equivalently kilogram meters per second (kg·m/s). The direction of the impulse matches the direction of the force.

The impulse-momentum relation provides a practical framework for analyzing interactions. For example, a bat hitting a ball applies an impulse that changes the ball’s velocity; a foot pushing off the ground exerts impulse that changes a person’s velocity. In engineering and safety analysis, impulses from impacts or propulsion are assessed by integrating the force over the contact time. When the force varies, the impulse is found by the time integral of F, or approximated by J ≈ Favg Δt for rough estimates.

Special cases include short-duration, high-magnitude impulses and long-duration, low-magnitude impulses. Understanding kokonaisimpulssi helps predict outcomes of interactions without requiring detailed knowledge of the instantaneous force profile.