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