# kilogram metre squared per second

##### SI coherent derived unit
Name Symbol Derived quantity
kilogram metre squared per second kg m2 s−1 angular momentum

### Definition

The kilogram metre squared per second, symbol kg m2 s−1, is the SI coherent derived unit of angular momentum.

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

$\text{kg} \ \text{m}^2 \ \text{s}^{-1} = \text{N} \ \text{m} \ \text{s} = \text{J} \ \text{s}$

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 m2 s−1, where the metre and the second are defined in terms of c and ΔνCs.

The effect of this definition is that the unit kilogram metre squared per second, symbol kg m2 s−1, can be defined directly in terms of the Planck constant h. Thus:

$h = 6.626\ 070\ 15 \times 10^{-34} \ \text{kg} \ \text{m}^2 \ \text{s}^{-1}\\ \\ \\ 1 \ \text{kg} \ \text{m}^2 \ \text{s}^{-1} = \dfrac{h}{6.626\ 070\ 15 \times 10^{-34}}$

### 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.