The Otto-cycle of a certain car has a compression ratio r=8.5. The fuel economy rating of this car is 25 miles per gallon at 105km/h. Gasoline has a heat of combustion of 4.60x10^7J/kg, and its density is 740kg/m^3.
a. At 105km/h, what is the rate of gasoline consumption in L/h?
b. What is the theoretical efficiency of the engine? Use γ=1.40
c. How much power is the engine producing at 105km/h? Assume that the engine is operating at its theoretical efficiency, and give your answer in watts and in horsepower. By comparison, the engine of the car has a maximum power of 236hp.
I think I have part b. using the termal efficiency formula for the otto cycle(e=1-1/(rγ-1)). The other two parts I'm completely stuck on.