To calculate the mass flow rate of blood in the aorta, use the equation m = pAv, where m is mass flow rate, p is density, A is cross-sectional area, and v is flow speed. Given a density of 1 g/cm³, a cross-sectional area of 2 cm², and a flow speed of 43 cm/s, the calculation can be performed directly in these units. However, to express the answer in g/s, it's essential to ensure that all units are compatible, particularly regarding the area and density. The user seeks clarification on whether unit conversions are necessary for accurate results. Ultimately, the correct application of the formula will yield the mass flow rate in the desired units.