YIKTLAI, 



IE*. EXAIIl'l.K. 



Pfl 



w cone* l*am brought into iu 



v two steps; first let it bo moved 





to itself till the lower end comes to A' t t revolve 



ugh an angle SB so as to bring the beam again 



^placement of A estimated 



along of action of R is c sin a. The displacement of 



G estimated vertically downwards is aS6 *'m - c co* a. 



Moreover there is a re la .seen 80, c, and a, arising 



from the fact that the whole displacement of the beam is such 

 as to keep the beam still in contact with the pi- i the 



tn;m-lr AHA . \u- li:i\- 



* c csin(0 o) > 



00 - j-^ ultimately. 



i|lo of virtual vcloci 



Wr, 8in f 08in (0-a)-ccosax + 7?csina-0; 

 that is, 



Il \ T Ijccoe +(./? 1~ sin*0 cos 1 e sin c 



\ o J \ b t 



and c cos a and c sin a are indepen reforo 



i . t 

 -^ 1-0, 7?- sin'^cos^-O; 







-, and 



jp 



