**kilogram metre squared per second**

##### SI coherent derived unit

Name | Symbol | Derived quantity | ||

kilogram metre squared per second | kg m^{2} s^{−1} |
angular momentum | ||

## DefinitionThe kilogram metre squared per second, symbol kg m |

The kilogram metre squared per second, is equivalent to the units newton metre second, symbol N m s, and joule second, symbol J s.

The kilogram is defined by taking the fixed numerical value of the Planck constant *h* to be 6.626 070 15 × 10^{−34} when expressed in the unit J s, which is equal to kg m^{2} s^{−1}, where the metre and the second are defined in terms of *c* and *Δν*_{Cs}.

The effect of this definition is that the unit kilogram metre squared per second, symbol kg m^{2} s^{−1}, can be defined directly in terms of the Planck constant *h*. Thus:

### Angular momentum

Angular momentum is the rotational equivalent of linear momentum. It is a conserved quantity – the total angular momentum of a closed system is constant.