A term used in biomechanical research. An impulse is a vector quantity associated with the momentum of a mass; when a force is applied to a rigid body it changes the momentum of that body. It is defined as an integral of a force with respect to time (i.e. the product of a force and the time which it is applied: a small force applied for a long time can produce the same momentum change as a large force applied briefly). Every moving body has an impulse, and through contact with other bodies this impulse can be transferred from one to the other.