Air exerts a significant drag force on moving objects. A motorcycle rider needs to keep the engine on when riding at constant speed on a flat surface to counter drag effects. Presume that all the engine's mechanical energy output is converted to work against drag, the rider/motorcycle has a cross-sectional area of 0.80 m², and a drag coefficient of 0.85 due to aerodynamic inefficiency. Take the density of air to be a typical 1.2 kg/m³ and the engine/transmission to be 31% efficient at converting chemical energy to mechanical energy. Determine the chemical energy intake of the engine in kCal ( 1 kCal = 4.19 kJ) when a rider travels at 50 km/h for 40 minutes.