| vector quantity equal to the product of the mass m of a body and the velocity v of its centre of mass, thus p = mv|
NOTE 1 For a continuous body in a domain D, momentum is equal to the integral , where ρ is the mass density in a domain having quasi-infinitesimal volume dV and mass dm, and velocity v. For a system of bodies, it is equal to the sum of their momentums.
NOTE 2 If the sum of external forces is equal to zero, momentum of a body follows a law of conservation.
NOTE 3 If the theory of relativity is applied, m is relativistic mass.
NOTE 4 The coherent SI unit of momentum is kilogram metre per second, kg·m·s−1.