MAM 01 





Wh.-n the sum ..:' the fore -s vanishes in Ai 1 

 the I,.) res reduce to a couple. 

 When -/' is not zero, tin- 

 forces can be rcdu< 



tant. For if 



2Px = 0, then ^.P acting 

 at is the single resultant. 



> be not = 0, let the 

 couple be transformed to one 

 in which each of the forces 



ial to 2P, and conse- 

 quently, by Art. 44, the arm 



'' . L.-t ^/'acting at A 



and !P acting along Oy' form this couple. The latter force- 

 is destroyed by the force ^/ > ah>n^ Oy t 1 1 nee the single 

 resultant is SP acting at A, that is, at a point the distance 



of which from is 



To find the resultant of >' "/forces which ad 



on a rigid body in one plane. 



Let the system be referred to any rectangular axes Ox, Oy 

 in the plane of the forces. 

 y 



Let P,, P f , P 3 , denote the forces; a,, a a , a 



the angles which their directions make -with the axis of a:; 



