A cattle watering has a free surface with a size equal to 0.6 m x 0.3m, with the longer side being parallel to the prevailing wind. Wind at -23 C is blowing over the surface at 1 m/s. A electrical heating element maintains the water surface AND interior temperatures at 10C.
Find the power needed for the heater. Assume that the bottom and sides of the container are perfectly insulated, the evaporative cooling is small, and water surface is level with the container top edge.