Center of Mass - A uniform gravitational field, is a concept in physics that describes the average position of the mass of an object. It is a point where the entire mass of an object can be considered to be concentrated for the purposes of analyzing its motion and behavior under the influence of external forces, such as gravity.
Planck Constant - A physical constant that relates the energy of one photon of electromagnetic waves to the frequency of that wave used in classic mechanics and quantum mechanics. Planck units are based on physical constants rather than human scales. The significance of the Planck constant arises in the context of Planck's law, which describes the spectral distribution of electromagnetic radiation emitted by a black body.