PROBLEM 5-72 (page 255, 12th edition) The pipe assembly is subjected to a force and couple moment as shown and is held in equilibrium by smooth journal bearings at A, B, and C. The bearings are in proper alignment and only exert force reactions on the pipe assembly. The weight of the pipe assembly may be neglected. · Determine the Cartesian components of these force reactions. Z 450 N C 0.6 m A 300 N · m 45° 0.4 m x 0.8 m 0.4 m B y PROB05_72.jpg Copyright @ 2010 Pearson Prentice Hall, Inc.
5-72 (page 255, 12th edition) COMPLETION OF PROBLEM (page 1): FORCES AND COUPLE MOMENT · Forces and couple (suppressing units) F = Ai+Ak Z FR = B i +Bk X Fc = C.j+Ck ! F = 450cos45 j ! 450sin45 k ! M = +300 j
5-72 (page 255, 12th edition) COMPLETION OF PROBLEM (page 2): EQUATIONS OF EQUILIBRIUM · Cartesian component force equations of equilibrium: ! F =0: × A+B =0 × ! F = 0: y C +450cos 45' = 0 y ! F = 0: A + B +C " 450sin45' = 0 2 Z Z N · Vector moment equation of equilibrium at point A: (MR)A =! M+!(+" F)=0=#300 j + ! ! i j ! k + 0 0.8 0 B X 0 B7 'z ! ! ! i j k + ! 0.6 1.2 0.4 + 0 Cy Cz ! i 0 1.2 0 450cos45 ! j " ! k 0.4 " ! 450sin 45 · Cartesian component moment equations of equilibrium: ! M =0: 0.8B +1.2C, "0.4C "1.2(450)sin45. "0.4(450)cos45! = 0 ! M =0: 0.6C " 300= 0 Z ! M =0: "0.8BB "0.6C =0 X