State the principle of conservation of angular momentum.

Explanation

It states that in the absence of external torque, total angular momentum of a system remains conserved.
As `vectau=(dvecL)/(dt)` If `vectau=0 ` , then `(dvecL)/(dt) = 0 implies vecL = ` constant.
SI unit of angular momentum is `kg m^2s^(-1)`