# A-level Physics (Advancing Physics)/Electron Behaviour as a Quantum Phenomenon/Momentum

All moving objects have momentum. Momentum is the product of the velocity of an object and its mass, so:

${\displaystyle p=mv\,}$

Momentum is usually denoted p, and is measured in kgms−1. Momentum is used when considering collisions of bodies as momentum, in a closed system, is constant. Force is the rate of change of momentum, so:

${\displaystyle F={\frac {\Delta p}{t}}}$