MOMENTA

Momentum, the singular form of MOMENTA, in physics, is the measure of movement: a quantity that expresses the motion of a body and its resistance to slow down. It is the fundamental quantity characterizing the motion of any object. Momentum is a vector quantity, which means that it has both magnitude and direction.
In philosophy Momentum is the basic element: an essential part of a whole.
Concerning physics, the total momentum of a system made up of a collection of objects is the vector sum of all the individual objects' momenta. For an isolated system, total momentum remains unchanged over time; this is called conservation of momentum. For example, when a batter hits a baseball, the momentum of the bat just before it strikes the ball plus the momentum of the pitched baseball is equal to the momentum of the bat after it strikes the ball plus the momentum of the hit baseball. As another example, imagine a beaver jumping off a stationary log that is floating on water. Before the beaver jumps, the log and the beaver are not moving, so the total momentum is zero. Upon jumping, the beaver acquires forward momentum, and at the same time the log moves in the other direction with an equal and opposite momentum; the total momentum of the beaver plus the log remains at zero.