The second law states that where dS ≥ dQ/T for a reversible process and dS = dQ/T for an irreversible process.
a. Show that since dW_{12} = -dW_{21} (dW_{reverse} = -dW_{forward}) for a reversible process, then dQ_{12} = TdS_{12}
b. An egg, initially at rest, is dropped onto the floor. Prove that this process is irreversible. You can assume that the egg returns to its initial temperature after it breaks.