Editing Momentum (section)

===Single particle===
The momentum of a particle is conventionally represented by the letter {{math|''p''}}. It is the product of two quantities, the particle's [[mass]] (represented by the letter {{math|''m''}}) and its [[velocity]] ({{math|''v''}}):<ref name=FeynmanCh9>[https://feynmanlectures.caltech.edu/I_09.html ''The Feynman Lectures on Physics''] Vol. I Ch. 9: Newton's Laws of Dynamics</ref>
<math qid=Q41273 display="block">p = m v. </math>

The unit of momentum is the product of the units of mass and velocity. In [[SI units]], if the mass is in kilograms and the velocity is in meters per second then the momentum is in kilogram meters per second (kg⋅m/s). In [[Centimetre–gram–second system of units|cgs units]], if the mass is in grams and the velocity in centimeters per second, then the momentum is in gram centimeters per second (g⋅cm/s).

Being a vector, momentum has magnitude and direction. For example, a 1&nbsp;kg model airplane, traveling due north at 1&nbsp;m/s in straight and level flight, has a momentum of 1&nbsp;kg⋅m/s due north measured with reference to the ground.