MKJLTAXT OF < 41 



r anus in the MID t line, and one 



lastly, let thrm be replaced by rrrtur 

 B tame arm ( 



. l the forces, and 

 r anna, 



:ill have thorn replaced by the following forces (cuppotinf 



a the r.' in mon arm), 



P.j, Q.- t .j acting on the arm . 



rcsuluuit will be a couple of which 

 eqoali 



R +-+*- 



an<l the arm a, 



or of which the moment equals 



resultant couple is equal to the sum 

 moments of the original couples. 



couples, as Q t Q, act in a direction ofpomk to 

 force at each extremity of the arm 



f the resultant couple will be 



ami the moment of the resultant couple will be 

 P.a-Q.b + Il.r + 



r tin- aL-vhraical sum of the moment* of the original 



cafe of those couples which tend in the 

 .0 couple /', 1* being reckoned negative. 



