All terms in this list:

Momentum: (of a body in motion) the product of its mass and velocity.

velocity: rate of change of position, or a speed with the directional component.

Newton's first law: The observation that objects in motion tend to stay in motion, and objects at rest tend to stay at rest unless an outside force acts upon them.

Newton's second law: Newton's observation that the rate of change of the momentum of a body is directly proportional to, and in the same direction as, the net force acting on it.

Newton's third law: Newton's observation that to every action (force applied) there is an equal but opposite reaction (equal force applied in the opposite direction)