P. Ortega  Palencia, Ruben Dario  Ortiz, Ana Magnolia Marin  Ramirez, 
    Hyperbolic Center of Mass for a System of Particles on the Poincare
Upper Half-Plane,
    Research Journal of Applied Sciences,
    Volume 14,Issue 2,
    2019,
    Pages 49-53,
    ISSN 1815-932x,
    rjasci.2019.49.53,
    (https://makhillpublications.co/view-article.php?doi=rjasci.2019.49.53)
    Abstract: In the present study, we obtain using the lever law of the lever, an explicit formula that allows to
calculate the center of mass of a system of n-particles with masses m<sub>1</sub>, m<sub>2</sub>, ..., m<sub>n</sub>>0, located on the half plane
superior of Lobachevsky H<sup>2</sup>, endowed with a conforming metric which induces constant and negative Gaussian
curvature.
    Keywords: The poincare upper half-plane model;hyperbolic center of mass;hyperbolic lever rule;Geodesic;particles;superior