To maintain a constant speed, the force provided by a car's engine must equal the drag force plus the force of friction of the road (the rolling resistance). The density of air is 1.2 kg/m³.

(a) What are the drag forces in newtons at 79 km/h and 108 km/h for a Toyota Camry? (Drag area = 0.70 m² and drag coefficient = 0.28.)

(b) What are the drag forces in newtons at 79 km/h and at 108 km/h for a Hummer H2? (Drag area = 2.44 m² and drag coefficient = 0.57.)