PROBLEM 3-53 (page 100, 12th edition) . Determine the force acting along the axis of each of the three struts needed to hold the 500 kg block in equilibrium. Z. D 1 B 2.5 m 2 m x 3 m 1.25 m 0.75 m y PROB03_53.jpg Copyright @ 2010 Pearson Prentice Hall, Inc.
PROBLEM 3-53 (page 100, 12th edition) COORDINATES 1 1 D ( - 1. 25 , - 2, 0 ) =) - . 1 1 1 1 1 - - - ( 1 0.75 , - 2,07 m 1 2 B(0,0,07m A ( 0, 3 , 2,5 ) m 1 1 1 1 5 - y
3-53 (page 110, 12th edition) COMPLETION OF PROBLEM (page 1) · Forces (suppressing units) FRA=(3j + 2.5k) X ! ! ! X = F / 32 +2.52 ! F. = (0.75 i ! 5 j ! 2.5 k) Y Y=F / v0.752+52 +2.52 AC Z = F / 1.252 +52 +2.52 : FAD= (!1.25 i ! 5 j ! 2.5 k) Z : ! = ! 500(9.81) k block · Equations of equilibrium ! F =F i+F ! R Rx1 Ry „j+F k =0 Rz F= ! F =0: 0.75Y ! 1.25Z =0 Rx X F= ! F =0: Ry y 3X!5Y !5Z = 0 F = ! F =0: Rz Z 2.5X ! 2.5Y ! 2.5Z ! 500(9.81)= 0 · Solving X = 4905 Y = 1839 Z = 1104 FD =19.2kN F =10.4kN AC AD F = 6.32kN