Linear Momentum is the product of the mass and the velocity of a moving object.Its SI meassurment unit is 1 kilogram-meters per second (1 kg*m/s).

Like velocity, momentum is a vector quantity (it has a magnitude and a direction):

\vec{p} = m\vec{v}

Conservation of Momentum

The linear momentum of a close system that isn't affected by any external forces is conserved.

Relation between Momentum and Force

From Netwon's Second law

\vec{F} = m\vec{a}

\vec{a} = \frac{d\vec{u}}{dt}

\vec{F} = m\frac{d\vec{u}}{dt}

\vec{F} = \frac{d\vec{p}}{dt}

Which means that the rate of change of the momentum of an object is proportional to the force F acting on it.