Translation dynamics of field-reversed configuration (FRC) plasmas are studied in the FRC Injection Experiment (FIX) machine. FRC plasmas have been formed in, and launched from, a field-reversed theta-pinch source, and subsequently translated into reduced external magnetic fields. When translated into an adjacent confinement region, incident velocity of the formed FRC exceeds the Alfven velocity. Moreover, the translated FRC cools less than the prediction of an adiabatic theory. The plasma reflects from an external mirror, and some of its axial kinetic energy is lost during every reflection. In this reflection process, significant plasma heating is observed in the case where the translation velocity exceeds the sound velocity.