Answer Happy

Suppose that the air resistance a car encounters is independent of its speed. When the car travels at 18 m/s, its engine delivers 18 hp to its wheels. (a) What is the power (in hp) delivered to the wheels when the car travels at 36 m/s? hp (b) How much energy (in MJ) does the car use in covering 10 km at 18 m/s? Assume that the engine is 25% efficient. MJ How much energy (in MJ) does the car use in covering 10 km at 36 m/s? Assume that the engine is 25% efficient. MJ Answer the same questions if the force of air resistance is proportional to the speed of the automobile. Still assume that when the car travels at 18 m/s, its engine delivers 18 hp to its wheels. (c) What is the power (in hp) delivered to the wheels when the car travels at 36 m/s? hp (d) How much energy (in MJ) does the car use in covering 10 km at 18 m/s? Assume that the engine is 25% efficient. MJ How much energy (in MJ) does the car use in covering 10 km at 36 m/s? Assume that the engine is 25% efficient. MJ (e) What do these results, plus your experience with gasoline consumption, tell you about air resistance?