The formula for calculating momentum is mass multiplied by velocity. An object's momentum is equivalent to its mass times its velocity, therefore the equation for momentum is the same. Momentum is measured in kilogram-meters per second, which are all standard metric units.
Momentum is a type of movement that every object contains. Objects in motion all have momentum that depends on their velocity and their mass. An object at rest does not have momentum because it has zero velocity. When calculating momentum, one must also calculate the direction in which the object is moving, since momentum is known as a vector quantity. This means that if an object is moving backwards, it may have negative momentum. However, the negative is only referring to the object's direction, not its motion.