Calculate the atmospheric pressure at an elevation of $3000 \mathrm{~m}$, assuming (a) air is incompressible, at a temperature of $59^{\circ} \mathrm{F}$; (b) air is isothermal at $59^{\circ} \mathrm{F}$ and an ideal gas; (c) the pressure distribution follows the model of the standard atmosphere, with a temperature of $59^{\circ} \mathrm{F}$ at the surface of the earth.