dE d=E, B e m First Laws of Thermodynamics de do dw d-M (V2-V12)+g(二2-=1)+(h2-h1) The energy equation per unit mass, dE E e dm  = = =  The energy equation per unit mass 2 2 2 1 2 1 2 1 1 ( ) ( ) ( ) 2 s q w V V g z z h h − = − + − + − First Laws of Thermodynamics dE dQ dW dt dt dt = −