Work out how much energy is saved by changing the bumper - set of a 1 000 kg car from steel to alumin um, over an assumed life of 200,000 km . T he energy consumption per kg per km for a 1000 kg car powered by gasoline i s 2.1 x 10 - 3 MJ/ ( km * kg )

The air in an automobile tire with a volume of 2.60 ft3 is at 70°f and 21 psig. determine the amount of air that must be added to raise the pressure to the recommended value of 30 psig. assume the atmospheric pressure to be 14.6 psia and the temperature and the volume to remain constant. the gas constant of air is ru = 53.34ft⋅lbflbm⋅r(1 psia144 lbf/ft2) = 0.3704 psia⋅ft3lbm⋅r the amount of air that must be added to raise the pressure is lbm