1.3 Energy of a System S.J.T.U. Phase Transformation and Applications Energy of system: ·Internal energy Potential energy:gravitational;centrifugal; electrical;and magnetic potential energies Kinetic energy:overall motion >Translational 》Rotational Have absolute value Internal energy:inherent qualities or properties Composition;physical form;environmental variables Temperature,pressure,electric and magnetic field,etc Mechanical(spring),chemical(H20),thermal energy(possessed) SJTU Thermodynamics of Materials Spring2010©X.J.Jin Lecture 1 First law I 19/38Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 1 First law I 19/38 1.3 Energy of a System Energy of system: • Internal energy • Potential energy: gravitational; centrifugal; electrical; and magnetic potential energies • Kinetic energy: overall motion » Translational » Rotational Internal energy: inherent qualities or properties Composition; physical form; environmental variables Temperature, pressure, electric and magnetic field, etc. Mechanical (spring), chemical (H2O), thermal energy (possessed) Have absolute value