Energy Transfer

MECHANICAL FORMS OF WORK (cont’d)• Two requirements exist for a work interactionbetween a system and its surroundings• There must be a force acting on the boundary• The boundary must move• Displacement of the boundary without any forceto oppose or drive this motion (such as theexpansion of a gas into an evacuated space) isnot a work interaction since no energy istransferred• Mechanical work is associated with themovement of the boundary of a system or withthe movement of the entire system as a wholeEnergy Transfer 11© Copyright 2005 Prof. Arun S. Mujumdar.