Impact Impulse

the impulse of the impulsive force acting on each of the colliding bodies during impact. The magnitude of the impact impulse is given by the equation S = P_av τ or

where P is the impulsive force, P_av is its average value during the time of impact, and τ is the duration of the impact. In the general theory of impact the impact impulse is regarded as a measure of the mechanical interaction of bodies during impact.