The momentum of the body is equal to the product of the mass and the velocity of that body:
p = mv (where p and v are vectors)
Where (SI units used):
p is the momentum in Newton seconds (Ns or sec Newtons, sN)
m is the mass of the body in kilograms (kg)
v is the velocity of the body in metres per second (ms^-1)
2. A tenis ball thrown at you at .5 ms^-1 will be pretty easy to stop with your face because it has little momentum.