# Change of entropy for an elastic ribbon under a tension

1. Sep 28, 2008

### vinirn

Introduction to Statistical Physics - Silvio Salinas:

Consider an elastic ribbon of length L under a tension f. In a quasi-static process, we can write:

dU = TdS + fdL + $$\mu$$dN

Suppose that the tension is increased very quickly, from f to f+df, keeping the temperature T fixed. Obtain an expression for the change of entropy just after reaching equilibrium. What is the change of entropy per mole for an elastic ribbon that behaves according to the equation of state L/N = cf/T, where c is a constant?

The tension is increased quickly, so is this a quasi-static process?