Momentum is a physical quantity that measures the mass of an object multiplied by its velocity. It is a vector quantity, meaning it has both magnitude and direction. Momentum is an important concept in physics, as it is related to the conservation of energy and momentum. Momentum is also used to describe the motion of objects in everyday life, such as a car or a ball. Momentum is represented by the symbol 'p' and is calculated by multiplying the mass of an object by its velocity.