This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Statistical Mechanics Homework Assignment 7 Due 30 October 2002 1. Problem 10.13 – Soap films (Reif 5.15) The figure illustrates a soap film (shown in gray) sup ported by a wire frame. Because of surface tension the film exerts a force 2 σl on the cross wire. This force is in such a direction that it tends to move this wire to decrease the area of the film. The quantity σ is called the “surface tension” of the film and the factor 2 occurs because the film has two surfaces. l x 2 l σ The temperature dependence of σ is given by σ = σ − αT where σ and α are constants independent of T and x . (a) Suppose that the distance x (or equivalently, the total film area 2 lx ) is the only external parameter of significance in the problem. Write a relation expressing the change dE in mean energy of the film in terms of the thermal energy T dS absorbed by it and the work done on it in an infinitesimal quasistatic process in which the distance x is changed by an amount dx ....
View
Full
Document
This note was uploaded on 03/17/2012 for the course PHYS 204 taught by Professor Atkin during the Spring '12 term at Amity University.
 Spring '12
 atkin
 Force, Work, Statistical Mechanics

Click to edit the document details