Atmospheric air is in parallel flow (u∞ = 15 m/s, T∞ = 15°C) over a flat heater surface that is to be maintained at a temperature of 140°C. The heater surface area is 0.25 m2, and the airflow is known to induce a drag force of 0.25 N on the heater. What is the electrical power needed to maintain the prescribed surface temperature?