
22 Ballistics: Theory and Design of Guns and Ammunition
energy comes about through adding heat to the system and doing work on the system.
Thus, work performed on the system is positive and heat added is also positive. Different
thermodynamics texts write the rst law slightly different, but if you understand that the
net result of work on the system or heat transfer to the system is to increase its energy, then
few mistakes will be made.
An interesting observation of Equation 2.40 is that the energy state change has an in-
nite number of paths that lead to the same result. For instance, if we wanted to add 24 kJ
of energy to some arbitrary system, ...