Under this model, a collision is completely described by the matrix , which refers to the constellation (i, j) before the collision, and the (in general different) constellation (k, l) after the collision. This notation is convenient in proving Boltzmann's H-theorem of statistical mechanics. Attack by means of a deliberate collision Types of attack by means of a deliberate collision include: striking with the body: unarmed striking, punching, kicking striking with a weapon, such as a sword, club or axe ramming with an object or vehicle, e.g.: Ram-raiding, the practice of driving a car into a building in order to break in a battering ram, medieval weapon used for breaking down large doors, also a modern version is used by police forces during raids An attacking collision with a distant object can be achieved by throwing or launching a projectile. See also Ballistic pendulum Car accident Coefficient of restitution Collision (telecommunications) Collision detection Contact mechanics Elastic collision Friction Head-on collision Impact crater Impact event Inelastic collision Kinetic theory of gases - collisions between molecules Mid-air collision Projectile Satellite collision Space debris Train wreck Notes References Reissued (1979) New York: Dover . External links Three Dimensional Collision - Oblique inelastic collision between two homogeneous spheres. One Dimensional Collision - One Dimensional Collision Flash Applet. Two Dimensional Collision - Two Dimensional Collision Flash Applet. Mechanics hu:Ütközés