

' of appli 



iatc axe*. Let 



' meet the plane of (x, y) at .V,, and draw 



jK'iuliculnr to H/-. Apply at -V, and aUo at O two 

 forces each equal and narallcl to /,, and in omxwitr direction*, 

 * Z^ at A % to /J, at O, an 



' 



1* supposed to act in the nlnm- of y. :'. nni 



i its moment = /., . OA\ and n , 'lane of (t, a?). 



We shall consider those couples as positive which tend to 



turn tlu- 1. : / to , also thoae 



body round the axis of y from r to s, 



an 1 thoi to turn the body round the axis of * 



'aced bv Z^ at 0, a couple # u v ; !* 



of (y, ), and a couple plane of (*, j- ^ : larly 



;iy be replaced by A', at O, a couj.l. plane 



. a?), and a couple - Aj, in the plane of (x, y). And >', 



may be replaced by )', at 0, a couple ) the plane 



y), and a couplo - > ne of (y, t). 



may be replaced 1 acting at /', and 



the moments are, by Art 48, 



!i the plane of (y, ) 9 



- - Y .y. 



