21 



( [U X u • !\)d:r = - J^ \ (R • w X A)n da 

 Using Gauss' theorem (remembering that n is directed outward from S-) 



<A)ncfa= \7 (R . fa, X A)c?T 

 - f (o 



I 



and 



(R 



A -v )RrfT 



(R X Id • q) n ( 

 Si 



(fe, X k)dT 



= — n l^ita X A) 

 3 



= -— 7t{w X A) 



3 



[44] 



p (r X w • h)q - (r X fc, • q) n d a = — n- (w X A) 



[45] 



By Equation [37] ^ the remaining term of Equation [40] can be written 

 0(nxa>)c?7=-a>xl $nc?£7= -— 77 (w x A) 



Combining Equations [44] and [46] we have 



and 



= -h"^-"^'«-"^"^^^"''"^]p^ 



[46] 



[47] 



[48] 



