﻿606 The late W. Gordon Brown on the 



Multiply this by -7- to find the value appropriate to unit 



length along the #--axis, and, taking the y-component, we 

 have 



--*[(if~£)»-tJMtf*49SiKI 



= fid x x 



[l{^(l)'-(l:)V"l!'-(|:/-'-(i9*)] 



= /"k|f (44) 



Hence the rate of change of momentum in the y-direction 

 per unit length along the #-axis is 



fe + vJ^^ = ^LS? +l< SSaJ- ' (4o) 



The force to be equated to this arises from the quasi- 

 tension 



E + VqB=^+//TqVqD 



= £+/*q.qd-^a.q 2 , 



of which the //-component is 



-^Mtr ♦•#)'} 



-£*.g+/*.J* (46) 



Differentiating with respect to x we have the force per 

 unit length 



<eS-^3J • • • • ^ 



