An impulsive force is a force which acts on an object for a short period of time. In a collision that results in a change in the velocity or momentum of one or more the objects involved in the collision, an impulsive force is primarily produced.
Impulsive forces are those forces that act on a body that change its state of motion for a brief interval, rather than being steadily continued by non-impulsive forces. A non-impulsive force is like the weight of the body, but an impulsive force is a driving body in an unexpected collision with another.
