All objects have mass therefore if an object is moving, then it has momentum – it has its mass in motion. Momentum depends upon the variables mass and velocity. We can change momentum by changing its mass or changing its velocity, a mass unit is multiplied by a velocity unit to provide a momentum unit. For example, a train moving at 120 km/h, a baseball flying through the air, a heavy truck moving, a bullet fired from a gun, when you throw a ball at someone and it hits him hard. It is an indication of how hard it would be to stop the object.
As we know all objects have some amount of mass, so when they move or in motion condition then these possess momentum. Momentum has both magnitude and direction as it is a vector quantity. The momentum of a particle is a measure of the time required for a constant force to bring it to rest. The momentum of any object that is at rest is 0. If the mass is kept constant, then the momentum of an object is directly proportional to its velocity. In terms of an equation, the momentum of an object is equal to the mass of the object times the velocity of the object.