Momentum is a characteristic of a moving object that is related to the mass and the velocity of the object. Conservation of momentum, in the presence of outside forces like friction, the total momentum of objects that interact doesn't change. the formula of momentum is, momentum=mass times velocity. P was a convenient symbol, M would be confused with mass. A moving van can have the same momentum as a motorcycle if the motorcycle is going fast(like 50 mph) and the van is going slow(like 5 mph). A "sticky" collision(inelastic collision) is when two objects collide together forming one bond and changing kinetic energy and a "non sticky" collision(elastic collision)is a kinetic model for molecular flow is developed to simulates the escape rate profiles that result when molecules are pulsed into the top of a cylindrical tube. I think throwing a piece of clay on the floor would be a "sticky" collision because it would stick. Angular momentum of a rigid object is defined as the product of the moment of inertia and the angular velocity. It is analougous to linear momentum and is subject to the fundamental constraints of the conservation of angular momentum principle if there is no external torque on the object. Angular momentum is a vector quantity.