Hailstones are formed in high altitude clouds at 253 K. Consider a hailstone with diameter of 20 mm and is falling through air at 11.25°C with convection heat transfer coefficient of 163 W/m2·K. Assuming the hailstone can be modeled as a sphere and has properties of ice at 253 K, determine the duration it takes to reach melting point at the surface of the falling hailstone. Solve this problem using analytical one-term approximation method (not the Heisler charts). The properties of ice are rho = 922 kg/m3, cp = 1945 J/kg·K, and k = 2.03 W/m·K.