Momentum of an object is defined as the product of of its mass and velocity.

p = mv

p = Momentum of the object in kilogram metres per second (kg ms -1)

m = Mass of the object in kilograms (kg)

v = Velocity of the object in metres per second (ms-1)

Momentum is a vector which direction is that of its velocity. A change in momentum will occur if the velocity is changed. This change is expressed as:

^p = p(f) - p(i)

where: ^p = the change in momentum (kg ms-1)

p(f) = final momentum (kg ms-1)

p(i) = initial momentum (kg ms-1)

If the final or intial momentum are unknown the formula can be brought down to:

^p = mv - mu

where: ^p = the change in momentum (kg ms-1)

m = Mass (kg)

v = final velocity (ms-1)

u = initial velocity (ms-1)