3_1_h

Determine the mass of each of the two cylinders if they cause a sag of s = 0.5 m when suspended from the rings at A and B. Note that s = 0 when the cylinders are removed.

3_1_d

a 200-kg engine is suspended from a vertical chain at A. A second chain is wrapped around the engine and held in position by the spreader bar BC. Determine the compressive force acting along the axis of the bar and the tension forces in segments BA and CA of the chain. Hint: Analyze equilibrium first at A, then at B.

3: Notes

Particle Equilibrium​

For a particle to be in equilibrium, all forces acting on the particle form a zero resultant force
It is necessary to draw a free body diagram to account for all the forces that act on a particle
F_R = ΣF = 0

2D​

The two scalar equations of force equilibrium can be applied with reference to an established x, y coordinate system

ΣF_x = 0
ΣF_y = 0​

TENSION & pulleys - The tension force in a continuous cable that passes over a pulley is constant throughout the cable to keep it in equilibrium
SPRING - If the problem involves an elastic spring, then the stretch or compression (s) of the spring can be related to the force applied to it

F = ks​

3D​

First express each force on the free-body diagram as a Cartesian vector, then when the forces are summed and set equal to zero, the i j & k components are also zero. 

ΣF_NET = 0
ΣF_x = 0
ΣF_y = 0
ΣF_z = 0
​