Chapter 5: Problem 7
Assuming that there is no transformation of mass to energy or vice versa, it is possible to write a continuity equation for mass. ( \(a\) ) If we use the continuity equation for charge as our model, what quantities correspond to \(\mathbf{J}\) and \(\rho_{v}\) ? (b) Given a cube \(1 \mathrm{~cm}\) on a side, experimental data show that the rates at which mass is leaving each of the six faces are \(10.25,-9.85,1.75,-2.00\), \(-4.05\), and \(4.45 \mathrm{mg} / \mathrm{s}\). If we assume that the cube is an incremental volume element, determine an approximate value for the time rate of change of density at its center.