A film of pyridine filled a rectangular wire loop in which one side could be moved. Given that the wire loop is 8.53 cm wide and that a force of 6.48 xx 10^(-3) N is needed to move the side, determine the value of the surface tension. What is the work necessary to stretch the film a distance of 0.1 cm?

A film of pyridine filled a rectangular wire loop in which one side co

1.	A film of pyridine filled a rectangular wire loop in which one side could be moved. Given that the wire loop is 8.53 cm wide and that a force of 6.48 xx 10^(-3) N is needed to move the side, determine the value of the surface tension. What is the work necessary to stretch the film a distance of 0.1 cm?
Answer» Solution :The FORCE is related to the surface tension y and the width `l` by: `F=2l gamma` `THEREFORE gamma =F/(2l) = (6.48 XX 10^(-3))/(2 xx 8.53 xx 10^(-2))` `=3.79 xx 10^(-2) NM^(-1)` As `gamma =("work done" (W))/("area (A)")` `w = gamma xx A = 2(3.79 xx 10^(-2)) xx (8.53 xx 10^(-2)) xx (0.1 xx 10^(-2))` `=6.5 xx 10^(-6)` J