2_1_k

The pole is subjected to the force F, which has components acting along the x, y, z axes as shown. If the magnitude of F is 3 kN, and = 30o and = 75o, determine the magnitudes of F and Fy.

2_1_j

The mast is subjected to the three forces shown. Determine the coordinate direction angles of F1 so that the resultant force acting on the mast is zero.

2_1_g

The upwards acting force of (F1 + F3) kN has to be counter balanced by Fa and Fb. Determine Fa and Fb so that its resultant acts vertically downwards with (F1 + F3) kN

3_1_j

The three cables are used to support the 800-N lamp. Determine the force developed in each cable for equilibrium.

3_1_i

the 200-lb uniform tank is suspended by means of the 6-ft-long cable, which is attached to the sides of the tank and passes over the small pulley located at O. If the cable can be attached at either points A and B, or C and D, determine which attachment produces the least amount of tension in the cable. What is this tension?

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_g

A continuous cable of total length 4 m is wrapped around the small pulleys at A, B, C, and D. If each spring is stretched 300 mm, determine the mass m of each block. Neglect the weight of the pulleys and cords. The springs are unstretched when d = 2 m.

3_1_f

Determine the force in each cable and the force F needed to hold the 4-kg lamp in the position shown. Hint: First analyze the equilibrium at B; then, using the result for the force in BC, analyze the equilibrium at C

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_1_c

The gusset plate is subjected to the forces of four members. Determine the force in member B and its proper orientation  for equilibrium. The forces are concurrent at point O. Take F = 12 kN.

3_1_b

Determine the magnitude and angle  of F so that the particle is in equilibrium

3_1_a

Determine the magnitudes of F1 and F2 so that the particle is in equilibrium

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
​