Gravitational mass ($m_{\mathrm{g}}$)

Passive gravitational mass is the coefficient in $\mathbf{F}=m_{\mathrm{g}}\mathbf{g}$ for an imposed Newtonian gravitational field. Active gravitational mass instead measures a body's contribution to the source of that field in Newton's law of universal gravitation. Universality of the ratio of passive gravitational mass to inertial mass is the Newtonian content of the weak equivalence principle. In general relativity, the source is the full stress-energy tensor, rather than a single scalar gravitational mass.