Momentum

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Physics Newtonian Mechanics Momentum

	Collisions:
	The collision is an event that occurs when two particles come in contact for a short duration of time so that they exert an impulsive force on each other. There are two types of collisions: (i) Elastic collision and (ii) Inelastic collision. These are described as follows: (i) Elastic collision: An elastic collision is a collision in which the total kinetic energy as well as momentum of the colliding bodies before collision is same as that after the occurrence of collision. The examples of elastic collisions are the Billiard-ball collisions and the collisions of air molecules with the walls of a container at normal temperatures. (ii) Inelastic Colision: An inelastic collision is a collision in which some of the kinetic energy of the colliding bodies is converted into internal energy and the total kinetic energy of the colliding bodies before collision is not same as that after the occurrence of collision even though the linear momentum is conserved. The examples of inelastic collision are the striking of a meteorite with the earth and the collision of a rubber ball with a hard surface. In the previous case the objects stick with each other where as in the later case this does not happen. Linear Momentum: Linear momentum of a particle of mass m and velocity v is defined as the product of mass and velocity and is given by the formula: p = mv This is called quantity of motion. It is a vector quantity and its direction is along the direction of velocity. Its unit is kg.m/s and its dimensions are ML/T in terms of mass length and time. If we have a group of particles then the momentum could be written as: