ISO I;AI.ANCE. 



(3) "When the balance is disturbed it should readily ; 

 to its state of rest, or '//. 



\\"c shall now consider how these requisites may be sati 

 To find how the requisites of a good balance may le sat, 

 Let P and Q be the weights in the scales; let 



C'be the fulcrum, h its distance from the straight Jim 

 which joins A and 7?. Let IJ'b;- the weight of the t 

 I: the distance of the centre of gravity of the bc.-un fr- 

 this centre oi y being supposed to lie on the ] 



dicular from C on the straight line which j< 



6 the weight of each scale; so that P and 

 ally through A, and Q and /S vertically thr.u;:h B 

 Let 6 be the angle which the beam makes with tl 



there is equilibrium. 



The sum of the moments of the weights round C will b( 



n there is equilibrium, by Art. 57. IS" (> nd| 



of the perpendicular from C on the line of action of PancH 



is acostf Asin#; the length of the perpc.ndieular from ( 



on the line of action of Q and S is a cos 6 -f // d tjf 



:h of the perpendicular from Con the line of action of fll 



in 0. Therefore 





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