Question

1. Constraints on the number of independently moving particles; i.e., on whether the particles must move as an aggregate or can move separately.

2. Constraints on the direction of motion.

3. Constraints on the volume in which the motion is executed

How thermodynamic properties, in particular Entropy, would now respond to these constraints.

Answer 1

When the motion between a pair is limited to a definite direction irrespective of the direction of force applied, then the motion is said to be a completely constrained motion. For example, a rectangular shaft revolving in a rectangular hole.