The radius of the earth is about 4,000 miles. if there were a global superhighway that circles around the entire equator of the earth, approximately how much would it cost for you to buy enough gas to drive around the earth once? assume that the gas costs $3.20 a gallon and that your car can get 25 miles per gallon.

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)