A cart runs along a straight level road by burning propane. For the cart, we can define efficiency as the ratio of energy expended to overcome air resistance to the energy available in the propane. The enthalpy for the combustion of propane
is given by
ΔHrea = –2.22 x 106 J/mol
In a given experiment, the cart (of mass m) travels a distance D at constant velocity v on a level road. It consumes n moles of propane during that time. The force due to the air resistance is Fair, which is proportional to the square of the velocity.
Where does the energy go which is not used to overcome air resistance?