I was reading about the Principle Of Equivalence as proposed by Einstein which proved that Inertial Mass and Gravitational Mass is one and the same thing. Further it proved that if we are in a spaceship and flying in space with acceleration 'g' upwards, the person is bound to the surface of the rocket and there's no experiment one can do to distinguish if the person is on earth or in a spaceship. So maybe what appears to us as the earth's gravitational pull, maybe just a pseudo force, maybe we are accelerating upwards? and we are pulled towards the surface of earth who knows?...It can be possible that we are in the wrong coordinate system, we have chosen / or we are living in a coordinate system , which leads to emergence of a pseudo force 'mg' and therefore we need to consider whenever we consider vertical motion as per Galilean Transformation. And as all pseudo forces are directly proportional to mass , mg does the same.