Wind at 30°C flows over a 0.5-m-diameter spherical tank containing iced water at 0°C with a velocity of 25 km/h. If the tank is thin-shelled with a high thermal conductivity material, what is the rate at which ice melts (in kg/h)? (Take heat of ice fusion hif = 333.7 kJ/kg, and use the following for air: k = 0.02588 W/m·K, Pr = 0.7282, ν = 1.608 × 10⁻⁵ m²/s, dynamic viscosity μ = 1.872 × 10⁻⁵ kg/m·s, and thermal diffusivity α = 1.729 × 10⁻⁵ kg/m·s).