CE Statics Chapter 5 Lectures 4 and 5 EQUILIBRIUM IN THREE DIMENSIONS Free-Body Diagram Equations of Equilibrium Free-Body Diagram It is necessary to draw free-body diagram before solving problems associated with equilibrium of bodies. Support Reactions Table 5-2 shows the reactive forces and couple moments acting at various types of supports and connections in three dimensions. Force is developed in the direction where translation of the body is prevented. Couple moment is developed in the direction where rotation of the body is prevented. Fy Fz Ball and SocketSingle Journal Bearing Single Journal Bearing with Square Shaft Equation of Equilibrium Vector Formulation F = 0 M o = 0 F represents the sum of all external forces acting on the body. M represents the sum of couple moments and moments of all forces about point O. Scalar Formulation F x = 0 F y = 0 F z = 0 and M x = 0 M y = 0 M z = 0 Six equation can be used to solve for six unknowns