- #1
daxowax
- 4
- 0
Hi,
In an article on theoretical fluid dynamics I recently came across the following equation:
$$M_i = \sqrt{g} \rho v_i$$
where ##M_i## denotes momentum density, ##v_i## velocity, ##\rho## the mass density and g is the determinant of the metric tensor. It is probably quite obvious, but I do not get why you have to put the ##\sqrt{g}## in there. Aren't both densities related to the same volume form? I would appreciate any help!
In an article on theoretical fluid dynamics I recently came across the following equation:
$$M_i = \sqrt{g} \rho v_i$$
where ##M_i## denotes momentum density, ##v_i## velocity, ##\rho## the mass density and g is the determinant of the metric tensor. It is probably quite obvious, but I do not get why you have to put the ##\sqrt{g}## in there. Aren't both densities related to the same volume form? I would appreciate any help!