Joule-second

The joule-second (symbol J⋅s or J s) is the unit of action and of angular momentum in the International System of Units (SI) equal to the product of an SI derived unit, the joule (J), and an SI base unit, the second (s). The joule-second is a unit of action or of angular momentum. The joule-second also appears in quantum mechanics within the definition of the Planck constant. Angular momentum is the product of an object's moment of inertia, with the unit kg⋅m² and its angular velocity with the unit rad⋅s⁻¹. This product of moment of inertia and angular velocity yields kg⋅m²⋅s⁻¹ or the joule-second. The Planck constant represents the energy of a wave, with the unit joule, divided by the frequency of that wave, wit the unit s⁻¹. This quotient of energy and frequency also yields the joule-second (J⋅s).