ENGR 34 Chapter 5, Day 2 2D Equilibrium of a Rigid Body a) 2D Equilibrium Equations b) 2 Force Bodies c) 3 Force Bodies

2D Equilibrium of a Rigid Body  F = 0 yields two scalar equations  M = 0 yields one scalar equation 2D Rigid Body magic # = 3 Note: 2D Point Equilib. magic # = 2

2 Force Bodies Forces co-linear, equal and opposite Short-cut uses up all three equations Identify & use (skipping the FBD & Equations)

3 Force Bodies Forces concurrent or parallel Short-cut uses up an equation

2D Equilibrium of a Rigid Body Key Concepts FBD must be compete, but nothing extra 2D RB Magic # = 3 (equations and unknowns) Moment equations may isolate unknowns