Lima and Monteiro [1[1] F.M.S. Lima and F.F. Monteiro, Rev. Bras. de Ensino de Fis. 35, 3701 (2013).] derived the buoyant force in a nonuniform gravitational field by applying a gradient version of the divergence theorem to the surface integral of the pressure forces [2[2] F.M.S. Lima, Eur. J. Phys. 33, 101 (2012).]. Here it is outlined an alternate approach in the framework of fluid mechanics, based on the energy formulations of the equations of state for compressible fluids.
Keywords:
buoyancy; Archimedes’ principle; nonuniform fields; potential energy minimization