2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/74655We present an explicit formula for the mean curvature of a unit vector field on a Riemannian manifold, using a special but natural frame. As applications, we treat some known and new examples of minimal unit vector fields. We also give an example of a vector field of constant mean curvature on the Lobachevsky $(n+1)$ space.Differential Geometry53B25, 53C25text