Problem 8-67 ( 27 th February ) m= 100 kg g= 9.81 m/s2 w= mg Q = 10° MA= 0.6 MB = 0.2 Mc = 0.3 Cartesian component equations of equilibrium : No moment equation for wedge since no tendency for wedge to rotate Wedge: EFx=0 : P-F2- FBCOSO - NBsino = 0 - (i) EFy= 0: Ne + FBsine - No Cost = 0 -(ii) Cylinder: IF == O: F & cose + NB sine - NA = 0 - (iii) EFy = 0: - FB sine + N& coSO - FA - W = 0 - (iv) E(M2)0 = 0: FAP = FBr - (v) Restrictions: FAS MANA FB 5 Mg NB Fc & Mc Ne unknowns : P, FA, NA, FB, NB, FC, Nc 7 unknowns => need 2 more Assume impending motion sliding at B and C Fc = McNc - (vi) FB = UBNB - ( vii) Solutions : P=857 N FA = FB = 262 N Fc = 373 N NA = 495 N NB : 1.31 KN Nc = 1.24 KN FA < MANA = (0.6) (485) - 201 N Smallest horizontal needed to lift cylinder is 857 N
Chapter 12 a ds = v dv